fix(model): remove _from_dict step in _convert_model

Author: ehdsouza

ibm_cloud_sdk_core/base_service.py

@@ -206,10 +206,6 @@ def prepare_request(self, method, url, headers=None,
 
     @staticmethod
     def _convert_model(val, classname=None):
-        if classname is not None and not hasattr(val, "_from_dict"):
-            if isinstance(val, str):
-                val = json_import.loads(val)
-            val = classname._from_dict(dict(val))
         if hasattr(val, "_to_dict"):
             return val._to_dict()
         return val