Bug 28861: Item type column always hidden in OPAC holds history

Bug 28861: Item type column always hidden in OPAC holds history

This patch fixes the 'Requested item  type' column not showing for holds
history in OPAC.

It was due to a template variable not being set. When solved, it become
clear that an import was missing for a template plugin.

To test:
1. Enable AllowHoldItemTypeSelection
2. Add a couple item-type constrained holds
3. See them in the holds history page
=> SUCCESS: Item type column shows
4. Enable OPACHoldsHistory
5. Look for them in the OPAC
=> FAIL: The item type column doesn't show
6. Apply this patch
7. Repeat 5
=> SUCCESS: The column shows! The item type is described!
8. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>