Updated auth instructions for "Google Auth Platform" experience

[dbarnett]

Is it worth updating the auth instructions to note Google's new recommended experience for configuring OAuth?

I went to set up auth on a new computer and after navigating to "OAuth consent screen" in Google Cloud Console I saw this prompt for their "new experience":

Clicking that took me to some alternative menus for project OAuth config:

The old way still works for now but the promo threatens it'll "only be available for a few more days".

[github-actions]

This issue is stale because it has been open for 30 days without activity.
This will be closed in 7 days, unless you add the 'lifecycle/keep-alive' label or comment.