Bug 35619: Fix validation error alignment in change password form

Bug 35619: Fix validation error alignment in change password form

Bug 31829 made a change to the change password form in the staff
interface to accommodate a gap in the CSS following the staff interface
redesign. This gap has been fixed, so we don't need a double class on
the fieldset.

With this change, the "hint" div can also be put back into place.

To test, apply the patch and locate a patron record in the staff
interface.

 - Click the "Change password" button on the patron detail page.
 - Confirm that the form layout looks correct.
 - Enter mismatched passwords in the "New password" and "Confirm new
   password" fields and click "Save"
   - The validation error message should be aligned to the right of the
     input field.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>