Remove restrictive 30 character limit from username of AuthenticationForm.
|Reported by:||SmileyChris||Owned by:||nobody|
|Has patch:||no||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
While #8274 at least makes it possible to override the form now, the current default doesn't make sense.
The AuthenticationForm is not directly tied to the User model - any backend could use it. Therefore, there should not be a default max_length for the username.