Fix call to get_immediate

synapse/storage/databases/main/roommember.py

@@ -624,7 +624,7 @@ async def get_rooms_for_user(self, user_id: str) -> FrozenSet[str]:
         participating in.
         """
         rooms = self.get_rooms_for_user_with_stream_ordering.cache.get_immediate(
-            user_id
+            (user_id,), None, update_metrics=False,
         )
         if rooms:
             return frozenset(r.room_id for r in rooms)