[feature] Make suggested username from OIDC all small caps automatically

[poVoq]

Is your feature request related to a problem ?

When I first create a user via the OIDC integration the suggested name from the OIDC provider comes with a mixed set of small and capital letters. This then fails to be accepted by the username check that seems to allow only small caps.

Describe the solution you'd like.

The automatically suggested name should be converted into all small letters to avoid confusing people why it doesn't work.

Describe alternatives you've considered.

The username check could ignore capitalized letters and just proceed with the name all in small letters.

Additional context.

No response