[gateway][idp][auth] handle login attempt failure when the IDP is configure to accept several username input

[remisultan]

💥 Describe the bug

When an IDP is configured to accept multiple username input (aliases) (email / username) the login attempt won't be initialised for the other username but only the one that AM considers aliases.

🌄 To Reproduce

Steps to reproduce the behaviour:

1. Configure Brute Force Detection
2. Fail to login with a user with already existing username but use an alias (e.g username = john.doe, email=john.doe@unknown.com) as many times as needed to activate brute force detection
3. Notice the user was not blocked

🌈 Expected behaviour

The user considering many of their aliases should be blocked

Current behaviour

The user considering many of their aliases is not blocked