operator+pkg: depend on clientset.Interface instead of *clientset.Clientset

[mohamedawnallah]

Description

In this commit, we apply the Dependency Inversion Principle by depending on an interface instead of a concrete type. This improves flexibility and testability.

Motivation and Context

While testing the Karmada Init and DeInit in the operator package (#5613), I found it difficult to mock *clientset.Clientset, complicating unit tests. By refactoring to depend on an interface, we improve flexibility and testability, allowing for the integration of a fake clientset since it implements that interface.

What type of PR is this?

/kind cleanup

Does this PR introduce a user-facing change?:

NONE

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 28.57143% with 5 lines in your changes missing coverage. Please review.

Project coverage is 35.19%. Comparing base (4c8bcd4) to head (a640f09).
Report is 62 commits behind head on master.

Files with missing lines	Patch %	Lines
operator/pkg/util/kubeconfig.go	0.00%	2 Missing ⚠️
pkg/karmadactl/cmdinit/karmada/deploy.go	0.00%	2 Missing ⚠️
pkg/karmadactl/util/apiclient/apiclient.go	0.00%	1 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5616      +/-   ##
==========================================
+ Coverage   34.14%   35.19%   +1.05%     
==========================================
  Files         643      645       +2     
  Lines       44524    44869     +345     
==========================================
+ Hits        15203    15792     +589     
+ Misses      28165    27846     -319     
- Partials     1156     1231      +75     

Flag	Coverage Δ
unittests	35.19% <28.57%> (+1.05%)	⬆️

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[RainbowMango]

/lgtm
/approve

Thanks @mohamedawnallah!

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

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