NGINX Ingress: port spec.clusterIP fixups

Bring in changes from upstream, fixing issues with spec.clusterIP immutability.

Issue: https://github.com/helm/charts/issues/19041

MRs:

• https://github.com/helm/charts/pull/19146
• https://github.com/helm/charts/pull/19161

This does not solve existing installations, but prevents problems with future deployments.

Closes #1710 (closed)

Replaces !1050 (closed)