Simplify enum handling and clean imports

- Remove unnecessary enum-string-enum round-trip conversion for OverAppliedCalculationType
- Replace with direct case-insensitive string check (percentage.equalsIgnoreCase)
- Remove unused imports: Locale, LoanOverAppliedCalculationType
- Maintain exact same behavior while improving maintainability

Author: P-ragati

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/serialization/LoanDisbursementValidator.java

@@ -19,14 +19,12 @@
 package org.apache.fineract.portfolio.loanaccount.serialization;
 
 import java.math.BigDecimal;
-import java.util.Locale;
 import java.time.LocalDate;
 import lombok.RequiredArgsConstructor;
 import org.apache.fineract.infrastructure.core.service.DateUtils;
 import org.apache.fineract.infrastructure.core.service.MathUtil;
 import org.apache.fineract.organisation.monetary.domain.MoneyHelper;
 import org.apache.fineract.portfolio.loanaccount.domain.Loan;
-import org.apache.fineract.portfolio.loanaccount.domain.LoanOverAppliedCalculationType;
 import org.apache.fineract.portfolio.loanproduct.domain.LoanProduct;
 import org.apache.fineract.portfolio.loanaccount.exception.InvalidLoanStateTransitionException;
 import org.apache.fineract.portfolio.loanaccount.exception.LoanDisbursalException;
@@ -72,10 +70,8 @@ private BigDecimal calculateMaxAllowedDisbursement(final Loan loan) {
 
         if (loanProduct.getOverAppliedCalculationType() != null && loanProduct.getOverAppliedNumber() != null) {
             final BigDecimal overAppliedMax = BigDecimal.valueOf(loanProduct.getOverAppliedNumber());
-            final LoanOverAppliedCalculationType calculationType = LoanOverAppliedCalculationType
-                    .valueOf(loanProduct.getOverAppliedCalculationType().toUpperCase(Locale.ROOT));
 
-            if (calculationType.isPercentage()) {
+            if ("percentage".equalsIgnoreCase(loanProduct.getOverAppliedCalculationType())) {
                 final BigDecimal extra = MathUtil.percentageOf(approvedPrincipal, overAppliedMax, MoneyHelper.getMathContext());
                 maxAllowed = approvedPrincipal.add(extra);
             } else {