cli_function: handle nargs="*" in config file

nargs="*" leads to default [] and not None

cli_function_test_config_2.py

@@ -3,3 +3,4 @@ def set_args(args):
     :type args: Dict[str, Any]
     '''
     args['bool_cli'] = False
+    args['args_star'] = ['asdf', 'qwer']