Cannot access oss-fuzz.com with multiple mail addresses attached to Google account

As outlined in https://google.github.io/oss-fuzz/faq/#why-do-you-require-a-google-account-for-authentication you need a Google account for authentication. It seems the documentation falls short since you actually also need a `@gmail.com` address which was mentioned in other places (sorry, I have no reference to such a mention at the moment). I am also curious why it offers login with a GitHub account if you are required to use a Google account - but let's stay on one issue at a time.

I had a Google account for a long time but only an external address attached to it so I also added a GMail one. I used that as an additional address because I do not want my regular notifications to go into a separate account (I am aware that I would need to look into the other account to see the OSS-Fuzz stuff). That address is shown to me in Chrome and also when I select an existing account to log in.

But I am not able to authenticate on https://oss-fuzz.com. It always says

```
You (email=) are not authorized to access this page!
```

I also tried a private tab and entered the `@gmail.com` address to log in and still the same. It seems like it is looking up the account via the given address but then uses the primary(?) account instead of the one used in the actual login.

https://issues.oss-fuzz.com seems to correctly use the `@gmail.com` as it is used in the default search term.

My address was only added to a project a few days ago in #12886 and I first thought it might not have been synchronized with the login but the issue still persists.