Good information, but you can already turn this off via the (quite hidden, I admit) setting that is mentioned in the article. That's a better way to turn this off completely, rather than patch it via a visual rule.
In the Brave community the only solution offered was an adblock filter: brave://adblock (custom filter) ||accounts.google.com/gsi/client$script,third-party
https://community.brave.com/t/annoying-login-with-google-pop...