Log the stack when waiting for an entire room to be un-partial stated (#13257)

The stack is already logged when waiting for an event to be un-partial
stated. Log the stack for rooms as well, to aid in debugging.

changelog.d/13257.misc

+Log the stack when waiting for an entire room to be un-partial stated.

synapse/storage/util/partial_state_events_tracker.py

@@ -166,6 +166,7 @@ class PartialCurrentStateTracker:
             logger.info(
                 "Awaiting un-partial-stating of room %s",
                 room_id,
+                stack_info=True,
             )
 
             await make_deferred_yieldable(d)