fix(util): prevent empty label value in GetOwnerLabel for 126-char resource names

[mdryaan]

Description

util.GetOwnerLabel splits resource names longer than 63 characters across multiple label keys using manual index arithmetic. A post-loop assignment at line 245 ran unconditionally after the inner break, assigning completeResourceName[j:] to a new label key even when j == len(completeResourceName) — which happens whenever the input length is an exact multiple of 63 (126, 189, 252, …). This produced a label key with an empty string value. Kubernetes accepts empty label values, so the resource was created without error, but any downstream label selector that expected the full split name would silently fail to match. The fix is a single guard: if j < len(completeResourceName). This PR also adds the first test file in the util/ package, with five table-driven cases covering all splitting branches including the edge case.

Fixes #386

How Has This Been Tested?

Created util/reconciliation_utility_test.go with TestGetOwnerLabel covering: name ≤ 63 chars, name = 63 chars, name = 64 chars (one overflow), name = 126
chars (the edge case — previously produced a third label key with empty value), and name = 127 chars (three labels, all non-empty). All five subtests pass with
go test ./util/... -v -run TestGetOwnerLabel. go build ./... passes.

Before fix

After fix

Checklist:

• The title of the PR states what changed and the related issues number (used for the release note).
• Does this PR requires documentation updates? — No.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas. — N/A.
• I have tested it for all user roles. — N/A.
• I have added all the required unit test cases.

Does this PR introduce a breaking change for other components like worker-operator?

No — the fix only affects resource names whose byte length is an exact multiple of 63. Previously those names produced a spurious empty-value label that would never match any selector; after the fix they do not. Any selector already working correctly is unaffected.

Fix util.GetOwnerLabel to not emit an empty-value label key when the resource name length is an exact multiple of 63