Bug 19276: (bug 17829 follow-up) Fix Statistic patrons behaviour

Bug 19276: (bug 17829 follow-up) Fix Statistic patrons behaviour

Bug 17829 must have been handle this specific case: GetMember set
category_type, but now $borrower is a Koha::Patron unblessed and does
not contain the category_type.
The fix is to call ->category->category_type on the Koha::Patron object
to be able to know if they are a statistic patrons.

Test plan:
Run the tests

Tests pass, as does QA test tool
Signed-off-by: Alex Buckley <alexbuckley@catalyst.net.nz>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>