Added tests for unifiedauth controller

[anujagrawal699]

Description:
This PR enhances the unit tests for the Unified Auth Controller in the unifiedauth package. The improvements aim to increase code reliability, maintainability, and test coverage for the Unified Auth Controller.

Additions and Modifications:

1. pkg/controllers/unifiedauth/unified_auth_controller_test.go

Test Coverage:

1. unified_auth_controller_test.go: 25.30% to 71.3%

Overall coverage of unifiedauth controller: 25.30% to 71.3%

What type of PR is this?
/kind failing-test
/kind feature

Which issue(s) this PR fixes:
Fixes a part of #5470

Does this PR introduce a user-facing change?:

NONE

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 35.01%. Comparing base (721107d) to head (32ae217).
Report is 4 commits behind head on master.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5600      +/-   ##
==========================================
+ Coverage   34.87%   35.01%   +0.14%     
==========================================
  Files         645      645              
  Lines       44833    44861      +28     
==========================================
+ Hits        15637    15710      +73     
+ Misses      27991    27936      -55     
- Partials     1205     1215      +10     

Flag	Coverage Δ
unittests	35.01% <ø> (+0.14%)	⬆️

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[XiShanYongYe-Chang]

/retest

[XiShanYongYe-Chang]

Thanks~
/lgtm
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: XiShanYongYe-Chang

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• pkg/controllers/OWNERS [XiShanYongYe-Chang]

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