Bug 28181: Filter out archived debit types in point of sale

Bug 28181: Filter out archived debit types in point of sale

The filter for only displaying un-archived debit types on the point of
sale page had been missed.

NOTE: It would be beneficial to move this to a default filter in the
Koha:: objects search method for both debit_types and credit_types.. but
I opted for the quick fix here to resolve the bug and will impliment
default filtering in a subsequent enhancement bug.

Test plan
1/ Archive a debit type that is marked as 'Can be sold'
2/ Go to the point of sale page and confirm the above debit type appears
3/ Apply the patch
4/ Confirm the debit type no longer appears in the point of sale page.

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>