Automatic merge from submit-queue (batch tested with PRs 49370, 49481)

client-gen: stop embedding of GroupVersion client intfs

It is undefined (or at least uncontrollable) which methods of the clientset apigroup
interfaces are actually inherited. Moreover, there might be nameconflicts between the
accessors and inherited methods. This PR removes the embedding to make it unambiguous.

```release-note
Enforce explicit references to API group client interfaces in clientsets to avoid ambiguity.
```