🐛 fix: 修复 dify 下删除对话的报错问题

fixes: #1226

Author: Soulter

packages/astrbot/main.py

@@ -880,8 +880,9 @@ async def del_conv(self, message: AstrMessageEvent):
         provider = self.context.get_using_provider()
         if provider and provider.meta().type == "dify":
             assert isinstance(provider, ProviderDify)
-            await provider.api_client.delete_chat_conv(message.unified_msg_origin)
-            provider.conversation_ids.pop(message.unified_msg_origin, None)
+            dify_cid = provider.conversation_ids.pop(message.unified_msg_origin, None)
+            if dify_cid:
+                await provider.api_client.delete_chat_conv(message.unified_msg_origin, dify_cid)
             message.set_result(
                 MessageEventResult().message(
                     "删除当前对话成功。不再处于对话状态，使用 /switch 序号 切换到其他对话或 /new 创建。"