Bug 26108: (bug 25855 follow-up) Call after_circ_action hook only if issue exists

Bug 26108: (bug 25855 follow-up) Call after_circ_action hook only if issue exists

AddReturn can be called on an item even if it's not checked out (to
trigger holds for instance).
The hook should (?) not be called in that situation

Test plan:
Confirm the above and that the following tests are now passing:
 t/db_dependent/SIP/Message.t
 t/db_dependent/Reserves.t
 t/db_dependent/Circulation/issue.t
 t/db_dependent/SIP/Transaction.t
 t/db_dependent/Circulation.t

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