Fix EndpointSliceController service deletion processing

[tnqn]

What type of PR is this?
/kind bug

What this PR does / why we need it:
syncService shouldn't return error if the service doesn't exist which
means it's triggered by service deletion, otherwise the service would be
enqueued repeatedly even its cleanup has been executed successfully.

This patch makes syncService return nil if the error is NotFound when
getting the service, like the other controllers do.

Which issue(s) this PR fixes:

Fixes #82995

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Fixed the bug that deleted services were processed by EndpointSliceController repeatedly even their cleanup were successful.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

Hi @tnqn. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[liggitt]

/assign @robscott

[robscott]

/ok-to-test

[robscott]

Hey @tnqn, thanks for your PR! This is a great catch. Once this PR gets in we should be able to get an approver from the new owners file.

/lgtm

[robscott]

/retest

[robscott]

/retest

[robscott]

/priority important-soon

[tnqn]

@robscott thanks for the review!

[robscott]

/assign @freehan

[freehan]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: freehan, tnqn

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• pkg/controller/endpointslice/OWNERS [freehan]

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