Bug 21774: Cloned item subfields disappear when editing an item

Bug 21774: Cloned item subfields disappear when editing an item

Bug 10306 changed behavior on cloning item subfields by no longer splitting
constructions like 'A | B' in item fields like ccode.

If it is really recommended to clone item subfields, I am not so sure
about. But this patch at least restores the possibility to do so while
we discuss if we should ;)

Test plan:
[1] Run Items.t
[2] Make an item subfield repeatable in framework. And test edit items.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Works as expected. Also fixes the display of collections on the items
table (on editing items).

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>