[auth] refactor how we handle Google OAuth

[hdoro]

Apparently we don't need to make an extra API call, see here:

https://discord.com/channels/841451783728529451/1357835008525729984/1373045729727217668

Also, to fix the Sign-in with Google issues, see thread in Discord: https://discord.com/channels/841451783728529451/1357833557053276211/1374020282750079120