Fix test failure on DeepSpeed (#29444)

* Fix test failure

* use item

src/transformers/trainer.py

@@ -2011,7 +2011,10 @@ class Trainer:
                             is_accelerate_available()
                             and self.accelerator.distributed_type == DistributedType.DEEPSPEED
                         ):
-                            grad_norm = model.get_global_grad_norm().item()
+                            grad_norm = model.get_global_grad_norm()
+                            # In some cases the grad norm may not return a float
+                            if hasattr(grad_norm, "item"):
+                                grad_norm = grad_norm.item()
                         else:
                             grad_norm = _grad_norm.item() if _grad_norm is not None else None