fix: tighten feishu mention trigger matching (openclaw#11088) thanks @openperf

Co-authored-by: 王春跃 <80630709+openperf@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

extensions/feishu/src/bot.ts

@@ -216,7 +216,7 @@ function parseMessageContent(content: string, messageType: string): string {
 function checkBotMentioned(event: FeishuMessageEvent, botOpenId?: string): boolean {
   const mentions = event.message.mentions ?? [];
   if (mentions.length === 0) return false;
-  if (!botOpenId) return mentions.length > 0;
+  if (!botOpenId) return false;
   return mentions.some((m) => m.id.open_id === botOpenId);
 }