Fix the issue of get empty EndpointSlice from cluster informer when report EndpointSlice

[XiShanYongYe-Chang]

What type of PR is this?

/kind bug

What this PR does / why we need it:

When the karmada-controller-manager is restarted, the servcie-export-controller will requeue the ServiceExport associated with the collected EndpointSlice resources for processing:

https://github.com/karmada-io/karmada/blob/bd5692f08a259c1a959dc3fd1944071be9fda729/pkg/controllers/mcs/service_export_controller.go#L149-L159

Then, during the processing, the EndpointSlice resource is obtained from the cluster cache:

https://github.com/karmada-io/karmada/blob/bd5692f08a259c1a959dc3fd1944071be9fda729/pkg/controllers/mcs/service_export_controller.go#L399-L421

The cache may not have been synchronized at this time, and an empty EndpointSlice list will be obtained, which will be deleted in the removeOrphanWork function.

Which issue(s) this PR fixes: Fixes #6433

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

karmada-controller-manager: fix the issue of get empty EndpointSlice from cluster informer when report EndpointSlice

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Codecov Report

Attention: Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.

Project coverage is 45.33%. Comparing base (5f4bd5e) to head (b0560d6).

Files with missing lines	Patch %	Lines
pkg/controllers/mcs/service_export_controller.go	0.00%	8 Missing :warning:

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6434      +/-   ##
==========================================
- Coverage   45.35%   45.33%   -0.03%     
==========================================
  Files         687      687              
  Lines       56384    56393       +9     
==========================================
- Hits        25572    25563       -9     
- Misses      29217    29233      +16     
- Partials     1595     1597       +2     

Flag	Coverage Δ
unittests	45.33% <0.00%> (-0.03%)	:arrow_down:

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[XiShanYongYe-Chang]

/retest

[RainbowMango]

Please cc me again once you figure out a better solution.

[XiShanYongYe-Chang]

Please cc me again once you figure out a better solution.

Another modification is to perform a check when using the cluster Informer, which introduces the cost of an additional cache check.

Apart from this, no better solution has been thought of for now.

[RainbowMango]

/retitle Ensure EndpointSlice informer cache is synced before reporting EndpointSlice

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

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• ~~pkg/controllers/OWNERS~~ [RainbowMango]

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[RainbowMango]

@zhzhuang-zju Just a reminder, this fix should be included in the next patch release.