Bug 30399: Make Patron.t pass even if mandatory attributes exist

Bug 30399: Make Patron.t pass even if mandatory attributes exist

t/db_dependent/Koha/Patron.t is failing if mandatory attributes already
exist in the DB. We can make it pass easily by deleting all the
attributes before we run the tests.

Test plan:
  prove t/db_dependent/Koha/Patron.t
must return green even if one mandatory patron attribute exists.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>