Automatic merge from submit-queue (batch tested with PRs 58716, 59977, 59316, 59884, 60117). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

remove deprecated /proxy paths

These were deprecated in v1.2.
ref https://github.com/kubernetes/kubernetes/issues/59885
```release-note
kube-apiserver: the root /proxy paths have been removed (deprecated since v1.2). Use the /proxy subresources on objects that support HTTP proxying.
```

@kubernetes/sig-api-machinery-api-reviews