35138 Defect content palette search bar disappears and system content types exposition (#35173)

### Proposed Changes
This PR solves two small issues in the content palette:

#### This PR fixes: #35138 Defect Search bar disappears
* Restore $shouldHideControls() signal, modified in the modernization
deploy.

#### This PR fixes: #35140 Spike System Content Types exposition
* Hide `system=true` Content Types (e.g., 'Dot Favorite Page') from
being exposed when a request to the `api/v1/contenttype/page` resource
is made.
* Add integration tests

This PR fixes: #35138
This PR fixes: #35140

Author: dario-daza

core-web/libs/portlets/edit-ema/portlet/src/lib/edit-ema-editor/components/dot-uve-palette/components/dot-uve-palette-list/dot-uve-palette-list.component.ts

@@ -9,7 +9,6 @@ import {
     effect,
     inject,
     input,
-    linkedSignal,
     OnInit,
     signal,
     untracked,
@@ -132,6 +131,7 @@ export class DotUvePaletteListComponent implements OnInit {
     protected readonly $skipNextSearch = signal(false);
     protected readonly $contextMenuItems = signal<MenuItem[]>([]);
     protected readonly $isSearching = signal<boolean>(false);
+    protected readonly $shouldHideControls = signal<boolean>(true);
     protected readonly $siteId = this.#globalStore.currentSiteId;
     protected readonly $contenttypes = this.#paletteListStore.contenttypes;
     protected readonly $contentlets = this.#paletteListStore.contentlets;
@@ -146,11 +146,6 @@ export class DotUvePaletteListComponent implements OnInit {
     protected readonly $isFavoritesList = this.#paletteListStore.$isFavoritesList;
     protected readonly status$ = toObservable(this.#paletteListStore.status);
 
-    protected readonly $shouldHideControls = linkedSignal({
-        source: this.$contenttypes,
-        computation: (contenttypes) => contenttypes.length === 0
-    });
-
     /**
      * Computed signal to determine the start index for the pagination.
      * @returns The start index for the pagination.
@@ -292,7 +287,7 @@ export class DotUvePaletteListComponent implements OnInit {
      * Handles the selection of a content type to view its contentlets.
      * Store handles query building, filter reset, and page reset automatically.
      *
-     * @param contentTypeName - The name of the content type to drill into
+     * @param selectedContentType - The name of the content type to drill into
      */
     protected onSelectContentType(selectedContentType: string) {
         this.#paletteListStore.getContentlets({ ...EMPTY_SEARCH_PARAMS, selectedContentType });
@@ -421,6 +416,7 @@ export class DotUvePaletteListComponent implements OnInit {
      * @private
      */
     #updateControlsVisibility() {
+        this.$shouldHideControls.set(false);
         this.status$
             .pipe(
                 filter(

core-web/libs/portlets/edit-ema/portlet/src/lib/edit-ema-editor/components/dot-uve-palette/models.ts

@@ -153,6 +153,7 @@ export const DEFAULT_PER_PAGE = 30;
 
 /**
  * Base content types included in the Content tab.
+ * Filter excludes DotCMSBaseTypesContentTypes FORMs and HTMLPAGEs to keep the Palette UI focused on standard content.
  */
 export const BASETYPES_FOR_CONTENT = [
     DotCMSBaseTypesContentTypes.CONTENT,

dotCMS/src/main/java/com/dotcms/rest/api/v1/contenttype/ContentTypeResource.java

@@ -1911,6 +1911,8 @@ public final ResponseEntityPaginatedDataView getPagesContentTypes(@Context final
         //Curated list of varNames ensures they belong into the passed BaseTypes
         List<String> typeVarNames = contentTypes.stream()
                 .filter(contentType -> baseContentTypes.contains(contentType.baseType()))
+                // Excludes system contentTypes
+                .filter(contentType -> !contentType.system())
                 .map(ContentType::variable)
                 .collect(Collectors.toList());
 

dotCMS/src/main/webapp/ext/uve/dot-uve.js

@@ -16,14 +16,20 @@
 import com.dotcms.contenttype.model.type.ContentType;
 import com.dotcms.contenttype.model.type.PersonaContentType;
 import com.dotcms.contenttype.transform.contenttype.JsonContentTypeTransformer;
+import com.dotcms.datagen.ContainerDataGen;
+import com.dotcms.datagen.ContentTypeDataGen;
+import com.dotcms.datagen.FolderDataGen;
+import com.dotcms.datagen.HTMLPageDataGen;
 import com.dotcms.datagen.SiteDataGen;
+import com.dotcms.datagen.TemplateDataGen;
 import com.dotcms.datagen.TestUserUtils;
 import com.dotcms.mock.request.MockAttributeRequest;
 import com.dotcms.mock.request.MockHeaderRequest;
 import com.dotcms.mock.request.MockHttpRequestIntegrationTest;
 import com.dotcms.mock.request.MockSessionRequest;
 import com.dotcms.rest.EmptyHttpResponse;
 import com.dotcms.rest.InitDataObject;
+import com.dotcms.rest.ResponseEntityPaginatedDataView;
 import com.dotcms.rest.ResponseEntityView;
 import com.dotcms.rest.RestUtilTest;
 import com.dotcms.rest.WebResource;
@@ -37,6 +43,10 @@
 import com.dotmarketing.business.PermissionAPI;
 import com.dotmarketing.exception.DotDataException;
 import com.dotmarketing.exception.DotSecurityException;
+import com.dotmarketing.portlets.containers.model.Container;
+import com.dotmarketing.portlets.folders.model.Folder;
+import com.dotmarketing.portlets.htmlpageasset.model.HTMLPageAsset;
+import com.dotmarketing.portlets.templates.model.Template;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.liferay.portal.model.User;
 import com.liferay.portal.util.WebKeys;
@@ -536,10 +546,61 @@ public void testGetRecentBaseTypes_whenCommunity_excludeTypes(final TestCase tes
 		assertEquals(testCase.typesIncluded, types.stream().anyMatch(this::isEnterpriseBaseType));
 	}
 
-	private boolean isEnterpriseBaseType(final BaseContentTypesView baseContentTypesView) {
-		return baseContentTypesView.getName().equals(BaseContentType.FORM.name())
-			|| baseContentTypesView.getName().equals(BaseContentType.PERSONA.name());
-	}
+    private boolean isEnterpriseBaseType(final BaseContentTypesView baseContentTypesView) {
+        return baseContentTypesView.getName().equals(BaseContentType.FORM.name())
+                || baseContentTypesView.getName().equals(BaseContentType.PERSONA.name());
+    }
+
+    /**
+     * Method to test: {@link ContentTypeResource#getPagesContentTypes}
+     * Given Scenario: A page whose container holds both a regular and a system content type
+     * ExpectedResult: System content types are excluded from the response; regular ones are included
+     */
+    @Test
+    public void test_getPagesContentTypes_excludesSystemContentTypes() throws Exception {
+
+        final User adminUser = APILocator.getUserAPI().loadUserById("dotcms.org.1");
+
+        final ContentType regularContentType = new ContentTypeDataGen().nextPersisted();
+        final ContentType systemContentType = new ContentTypeDataGen().system(true).nextPersisted();
+
+        try {
+            final Container container = new ContainerDataGen()
+                    .withContentType(regularContentType, "")
+                    .withContentType(systemContentType, "")
+                    .nextPersisted();
+            ContainerDataGen.publish(container);
+
+            final Template template = new TemplateDataGen()
+                    .withContainer(container.getIdentifier())
+                    .nextPersisted();
+            APILocator.getVersionableAPI().setLive(template);
+
+            final Host systemHost = APILocator.getHostAPI()
+                    .findSystemHost(adminUser, false);
+            final Folder folder = new FolderDataGen().site(systemHost).nextPersisted();
+            final HTMLPageAsset page = new HTMLPageDataGen(folder, template).nextPersisted();
+            APILocator.getContentletAPI().publish(page, adminUser, false);
+
+            final ContentTypeResource resource = new ContentTypeResource();
+            final ResponseEntityPaginatedDataView response = resource.getPagesContentTypes(
+                    getHttpRequest(), new EmptyHttpResponse(),
+                    page.getIdentifier(), "-1", null, 1, 10, "name", "ASC", null, null);
+
+            @SuppressWarnings("unchecked") final List<Map<String, Object>> contentTypes = (List<Map<String, Object>>) response.getEntity();
+            final List<String> variables = contentTypes.stream()
+                    .map(ct -> (String) ct.get(ContentTypesPaginator.VARIABLE))
+                    .collect(Collectors.toList());
+
+            assertTrue("Regular content type should be included in the palette",
+                    variables.contains(regularContentType.variable()));
+            assertFalse("System content type should be excluded from the palette",
+                    variables.contains(systemContentType.variable()));
+        } finally {
+            ContentTypeDataGen.remove(regularContentType);
+            ContentTypeDataGen.remove(systemContentType);
+        }
+    }
 
 	private static class TestHashMap<K, V> extends HashMap<K, V> {
 		@Override