[bugfix][memory]modified get_msg_by_role_name func

Author: yunjiu

muagent/connector/memory_manager.py

@@ -870,7 +870,8 @@ def init_global_msg(self, chat_index: str, role_name: str, role_content: str, ro
             return False
 
     def get_msg_by_role_name(self, chat_index: str, role_name: str) -> Optional[Message]:
-        memory = self.get_memory_pool(chat_index)
+        memory = self.get_memory_pool_by_all({"chat_index": chat_index, "role_name": role_name})
+        # memory = self.get_memory_pool(chat_index)
         for msg in memory.messages:
             if msg.role_name == role_name:
                 return msg