fix config type caused by timm version

Signed-off-by: ChengZi <chen.zhang@zilliz.com>

isc.py

@@ -128,6 +128,8 @@ class Isc(NNOperator):
     @property
     def config(self):
         config = get_pretrained_cfg(self.timm_backbone)
+        if hasattr(config, 'to_dict'):
+            config = config.to_dict()
         return config
 
     def save_model(self, format: str = 'pytorch', path: str = 'default'):