Support null for EndpointSlice.endpoints per updated Kubernetes OpenAPI #4506
Description
Describe the bug
The Kubernetes Java client fails to deserialize EndpointSlice objects when the API server returns "endpoints": null.
This happens when a Service has no backing Pods (e.g., scaled to zero or no selector match).
The client expects endpoints to be a JSON array, but recent upstream spec updates allow it to be null.
Upstream Kubernetes has fixed this behavior in kubernetes/kubernetes#136111, making endpoints nullable in the OpenAPI schema. (not released yet)
The Java client should be updated to allow null values for endpoints.