add card message callback

app/utils/xbot_utils.py

@@ -419,7 +419,7 @@ def send_select_activity_card_message(message_id):
         .message_id(message_id)
         .request_body(
             ReplyMessageRequestBody.builder()
-            .content(content=content)
+            .content(content=json.dumps(content))
             .msg_type("text")
             .reply_in_thread(True)
             .build()