fix(profile): autofocus when email is required, enter to submit, fix validation

This is just a small fix to an issue that was bugging me. Email entry for a new user didn't autofocus, didn't submit when you pressed the Enter key, didn't actually validate the email address correctly (e.g., you could enter 'a@b' and it would be accepted as valid), and continued to show an "Email required" validation warning on the email field even after a valid email address had been entered.