[nnUNet/PyT] fix pyprof import

PyTorch/Segmentation/nnUNet/main.py

@@ -14,7 +14,6 @@
 
 import os
 
-import pyprof
 import torch
 from pytorch_lightning import Trainer, seed_everything
 from pytorch_lightning.callbacks import EarlyStopping, ModelCheckpoint
@@ -29,6 +28,7 @@ if __name__ == "__main__":
     args = get_main_args()
 
     if args.profile:
+        import pyprof
         pyprof.init(enable_function_stack=True)
         print("Profiling enabled")