Bug 37031: Club enrollment from staff interface fails due to Entrollment typo

Bug 37031: Club enrollment from staff interface fails due to Entrollment typo

There is a typo in svc/club/enroll - it tries to call
Koha::Club::Entrollments->search when it should be
Koha::Club::Enrollments. This causes and error when
enrolling patrons in clubs.

Test plan:
1. Without the patch, Tools - Patron clubs - New club template - name it
   and save
2. New club - (your template) - name it and save
3. Circulation - check out to a patron - Clubs tab - Enroll - Finish
   enrollment, get alert() about failure to enroll
4. Apply patch, restart_all
5. Enroll - Finish enrollment, success

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>