removing uncessary line

Author: Rishab87

jupyter_server/services/contents/filemanager.py

@@ -807,7 +807,6 @@ async def _dir_model(self, path, content=True):
 
         if content:
             model["content"] = contents = []
-            dir_contents = await run_sync(os.listdir, os_dir)
             for name in dir_contents:
                 try:
                     os_path = os.path.join(os_dir, name)