Refactor _get_rank utility to take strategy instead of trainer (#14546)

Author: awaelchli

src/pytorch_lightning/callbacks/early_stopping.py

@@ -261,7 +261,7 @@ def _improvement_message(self, current: Tensor) -> str:
 
     @staticmethod
     def _log_info(trainer: Optional["pl.Trainer"], message: str, log_rank_zero_only: bool) -> None:
-        rank = _get_rank(trainer)
+        rank = _get_rank(strategy=(trainer.strategy if trainer is not None else None))
         if trainer is not None and trainer.world_size <= 1:
             rank = None
         message = rank_prefixed_message(message, rank)