Making use of Koha::Checkouts make the code much more readable here.
It fixes 2 flaws:
* $type was not quote escaped
* the effective itemtype was not used which could lead to wrong
calculation (for instance item-level_itypes is set but the item does
not have the itype defined)
However there is something to note, we are going to make things a bit
less effective as we are now fetching the items to get their effective
itemtype (vs a SUM done at DB level)
Signed-off-by: Nick Clemens <nick@bywatersolutions.com> Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io> Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>