Normalize_emails: user+x@gmail.com에서 user@gmail.com으로 이메일 주소를 변경할 수 없음

[supermathie (Michael Brown)]

@RGJ

If the user tries to change the email and the normalized email addresses are the same, it should simply change it without any further process.

This is dangerous if applied to any email provider, but if we limit it to gmail addresses this is fine.