Allow callbacks to be restored not just during training

Author: Alan Chu

src/lightning/pytorch/trainer/connectors/checkpoint_connector.py

@@ -397,9 +397,7 @@ def _restore_modules_and_callbacks(self, checkpoint_path: Optional[_PATH] = None
         self.resume_start(checkpoint_path)
         self.restore_model()
         self.restore_datamodule()
-        if self.trainer.state.fn == TrainerFn.FITTING:
-            # restore callback states
-            self.restore_callbacks()
+        self.restore_callbacks()
 
     def dump_checkpoint(self, weights_only: bool = False) -> dict:
         """Creating a model checkpoint dictionary object from various component states.