Adding a callback option to the Google OAuth provider used to define the OAuth callback URI. If not defined, the
callback URI will use the default value in the .env file.
provides the option to define a callback URI following a request from the frontend; if not defined, it will
automatically use the backend's default URI.
Create a flow where if the user logs in with a registered Google account, they are immediately authenticated, but if no
account is found, create a new one.
