Bugfix/username error

What does this MR do and why?

• Fix user errors where they were not showing up following a change made in 4.5.0.
• Remove triple option for validation and use sole robust error.
• Allow numeric passwords.
• Fix password dialogue closing with no indicator the password did not change when the passwords did not match.
• Allow use of enter key on password form.

Screenshots or screen recordings

How to set up and validate locally

• Log in
• Go to account settings
• Enter a username less than 3 characters or a username that has a capital.
• Change password to be 12345678 (we should have a vulnerable password check eventually)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Have you checked this doesn't interfere/conflict/duplicate someone elses work?
• Have you fully tested your changes?
• Have you resolved any lint issues?
• Have you assigned a reviewer?
• Have you applied correct labels?