Bug 22910: Do not copy unique patron attributes to duplicated patron

Bug 22910: Do not copy unique patron attributes to duplicated patron

When creating a new patron by duplicating another, all of the patron
attributes are also copied into the form. Some of those value may be
unique, so don't copy those.

1) Create patron attribute types, one with "unique identifier", one without.
2) Create or a patron so it has values in both of those attributes.
3) Duplicate the patron
4) The edit form should retain the values from the "original" patron.
5) Apply patch.
6) Duplicate the patron - this time the attributes with unique values
   are cleared.

Signed-off-by: Pasi Kallinen <pasi.kallinen@koha-suomi.fi>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>