The fix for that would be to modify the XSS config to allow it from here
-/libs/cq/xssprotection/config.xmlBut, please note that it's not
recommended to modify it. This html is not allowed as per the XSS config
(I am not aware of the reason). So, best is to avoid using this. You
could try to search on google if it's a valid and secured html. If it
is, you can try to modify the xml