Updating EndpointSlice controller to wait for all caches to be synced

[robscott]

What type of PR is this?
/kind bug

What this PR does / why we need it:
Previously the EndpointSlice controller was not waiting for EndpointSlices or Nodes to be synced.

Special notes for your reviewer:
As identified by @liggitt in #93496 (comment)

Does this PR introduce a user-facing change?:

The EndpointSlice controller now waits for EndpointSlice and Node caches to be synced before starting.

/sig network
/priority critical-urgent
/cc @freehan @liggitt

[liggitt]

thanks, did you sweep all the controllers involved in endpointslices to make sure they waited for caches correctly?

[liggitt]

/lgtm
/approve
/milestone v1.19

required to avoid endpointslice churn on startup. this should be picked to all releases where the controller was enabled

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[robscott]

@liggitt thanks for checking! I did confirm that both Endpoints and EndpointSliceMirroring controllers are waiting for the appropriate caches. For the record, EndpointSliceMirroring waits for endpoints, endpointslices, and services. Endpoints waits for pods, services, and endpoints.