Rebuild worker StatefulSet entirely from the leader's revision (#963)

When a not-yet-updated group's leader pod is recreated during a rolling
update, the worker StatefulSet is rebuilt from the leader's
ControllerRevision. Only the pod template was taken from the revision;
size (replicas and the size annotation), subGroupPolicy, networkConfig,
volume claim templates and the PVC retention policy were read from the
live spec. A rolling update that changes any of these left the rebuilt
old-revision group inconsistent, e.g. a size change 4->2 rebuilt the
group with 1 worker while its old-revision pods expect 3.

Read all revision-covered fields from the revision-applied spec instead.
Metadata (name, labels, annotations) is intentionally still read from
the live object since it is not part of the revision.

Co-authored-by: tomsen-ai <230283659+tomsen-ai@users.noreply.github.com>