fix(feishu): register group chat member event handlers

Bot-added and bot-removed events were silently dropped because
_on_bot_added_to_chat and _on_bot_removed_from_chat were not
registered in _build_event_handler().

From #6975

gateway/platforms/feishu.py

@@ -1190,6 +1190,8 @@ class FeishuAdapter(BasePlatformAdapter):
                 lambda data: self._on_reaction_event("im.message.reaction.deleted_v1", data)
             )
             .register_p2_card_action_trigger(self._on_card_action_trigger)
+            .register_p2_im_chat_member_bot_added_v1(self._on_bot_added_to_chat)
+            .register_p2_im_chat_member_bot_deleted_v1(self._on_bot_removed_from_chat)
             .build()
         )