Revert D86540593: Fix instances where report is not a string.

Differential Revision:
D86540593

Original commit changeset: 42f3dc51d667

Original Phabricator Diff: D86540593

fbshipit-source-id: b39c7c938585b0d165d18b3a43416cce827b2a11

Author: zdevito

python/monarch/_src/actor/actor_mesh.py

@@ -274,7 +274,7 @@ def filter(self, record: Any) -> bool:
         fn = _monarch_actor().per_actor_logging_prefix
         ctx = _context.get(None)
         if ctx is not None and fn is not None:
-            record.msg = f"{fn(ctx.actor_instance)}{record.msg}"
+            record.msg = fn(ctx.actor_instance) + record.msg
         return True