Bug 25460: Add unit test for change to C4::OAI::Sets->UpdateOAISetsBiblio()

Bug 25460: Add unit test for change to C4::OAI::Sets->UpdateOAISetsBiblio()

Test plan:

1. Run unit test:
sudo koha-shell <instancename>
prove t/db_dependent/OAI/Sets.t

2. All tests should pass

Sponsored-by: Catalyst IT
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
JD amended patch: Put tests inside a subtest, and perltidy

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>