The auth forms using SetPasswordMixin were incorrectly including the
'This field is required.' error when additional validations (e.g.,
overriding `clean_password1`) were performed and failed.
This fix ensures accurate error reporting for password fields.
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
Backport of 339977d4441fd353e20950b98bad3d42afb1f126 from main.