fix: improve error handling for non-existent conversation records

Author: liuruibin

apps/chat/serializers/chat.py

@@ -384,9 +384,8 @@ def get_chat_record(chat_info, chat_record_id):
                 return chat_record_list[-1]
             chat_record = QuerySet(ChatRecord).filter(id=chat_record_id, chat_id=chat_info.chat_id).first()
             if chat_record is None:
-                raise ChatException(500, _("Conversation record does not exist"))
-            
-            return chat_record
+                if not is_valid_uuid(chat_record_id):
+                    raise ChatException(500, _("Conversation record does not exist"))
         chat_record = QuerySet(ChatRecord).filter(id=chat_record_id).first()
         return chat_record