Summary:

This displays a descriptive error message for those who logged in with an email and got a null FedID back (because they don't have FedIDs yet)

Changes:

• Display message for null FedIDs

To test:

• Log in with a test Keycloak user that has no FedID (or modify getUser in the authentication method you're using, so it always returns null)
• Check if a message asking you to log in with your FedID is displayed
• Repeat by logging with your FedID (if you modified getUser, undo your changes), check if you can log in as normal