sync: Exclude stateless sync pruned projects from bloat check

If a project has been pruned for stateless sync, it has already
undergone aggressive garbage collection. There should be no bloat
to check for.

Change-Id: I9233a4611e05b7a0b7c097827d6f408144f7380d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/581841
Tested-by: Gavin Mak <gavinmak@google.com>
Reviewed-by: Becky Siegel <beckysiegel@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>

subcmds/sync.py

@@ -1459,7 +1459,11 @@ later is required to fix a server side protocol bug.
         if not git_require((2, 23, 0)):
             return
 
-        projects = [p for p in projects if p.clone_depth]
+        projects = [
+            p
+            for p in projects
+            if p.clone_depth and not p.stateless_prune_needed
+        ]
         if not projects:
             return