Fix errors detected by Ruff (#3918)

### What problem does this PR solve?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

intergrations/chatgpt-on-wechat/plugins/__init__.py

@@ -1 +1,5 @@
-from .ragflow_chat import *
+from .ragflow_chat import RAGFlowChat
+
+__all__ = [
+    "RAGFlowChat"
+]

intergrations/chatgpt-on-wechat/plugins/ragflow_chat.py

@@ -2,7 +2,6 @@ import logging
 import requests
 from bridge.context import ContextType  # Import Context, ContextType
 from bridge.reply import Reply, ReplyType  # Import Reply, ReplyType
-from bridge import *
 from plugins import Plugin, register  # Import Plugin and register
 from plugins.event import Event, EventContext, EventAction  # Import event-related classes