phases: drop set building in `hasnonpublicphases`

We don't actually use the set, so why do we ensure they are built?

(we should also clean up the use of repository argument but that's a quest for later).

mercurial/phases.py

@@ -382,8 +382,7 b' class phasecache:'
 
     def hasnonpublicphases(self, repo: "localrepo.localrepository") -> bool:
         """detect if there are revisions with non-public phase"""
-        repo = repo.unfiltered()
-        self._ensure_phase_sets(repo)
+        # XXX deprecate the unused repo argument
         return any(
             revs for phase, revs in self._phaseroots.items() if phase != public
         )