[Auth-UI] [v10.0.0-beta03] In AuthProvider.Email the signup form never becomes valid

[nerocristallo]

In AuthProvider.Email the signup form never becomes valid.

The signup button remains disabled because of SignUpUI validates displayName even when isDisplayNameRequired == false and the name field is hidden. Since the hidden value stays empty, the form never becomes valid.

[demolaf]

Hi @nerocristallo thanks for raising this. Seems like a pretty straightforward fix, if you want to take a jab at it?

[demolaf]

There's a PR to fix this #2383