fix: prevent wecom ai bot long connection replies from disappearing (#6606)

* fix: prevent empty fallback replies from clearing wecom ai bot output

* fix: 优化消息发送逻辑，避免发送空消息

---------

Co-authored-by: shijianhuai <shijianhuai@simuwang.com>
Co-authored-by: Soulter <905617992@qq.com>

astrbot/core/pipeline/scheduler.py

@@ -86,8 +86,10 @@ class PipelineScheduler:
         try:
             await self._process_stages(event)
 
-            # 如果没有发送操作, 则发送一个空消息, 以便于后续的处理
-            if isinstance(event, WebChatMessageEvent | WecomAIBotMessageEvent):
+            # 发送一个空消息, 以便于后续的处理
+            if (
+                isinstance(event, WebChatMessageEvent | WecomAIBotMessageEvent)
+            ):
                 await event.send(None)
 
             logger.debug("pipeline 执行完毕。")

astrbot/core/platform/sources/wecom_ai_bot/wecomai_event.py

@@ -135,6 +135,8 @@ class WecomAIBotMessageEvent(AstrMessageEvent):
 
     async def send(self, message: MessageChain | None) -> None:
         """发送消息"""
+        if message is None:
+            return
         raw = self.message_obj.raw_message
         assert isinstance(raw, dict), (
             "wecom_ai_bot platform event raw_message should be a dict"