Issue with Username Validation on User Registration & Edit

When administrator have enabled registration by e-mail on website, then Username field is no longer required.

This sounds good, but since we have username length validation always enabled, then I still get "Field value length is out of range, possible value length from 3 to 255" error for Username field.

SOLUTION:

We need to remove Length validation from Username field when it's EMPTY, but have it checked if it's 1+ symbols long.

This should be checked to be working on Front and Admin.