Reject authentication with Cilogon->Google

[knikolla]

Currently there are two ways to authenticate through Google. One is through CILogon, and then selecting Google, the other is to select Google directly.

If a user has a university Google account, and then use that to authenticate by following the CILogon->Google route, it is going to make it impossible for them to authenticate with CILogon->University if the email is the same, since the email is going to be the same, but Keycloak will reject matching it to the same user.

Figure out a way to prevent this.