Bug 8684: Fix duplicate check on creating items in the acquisition module

Bug 8684: Fix duplicate check on creating items in the acquisition module

The script acqui/check_uniqueness.pl has been introduced by bug 7178.
But bug 11425 added a call to a new subroutine SearchItemsByField in
order to refactore some code. This subroutine calls SearchItems with an
arrayref, which is not what SearchItems is expecting.
This broke the duplicate check done on creating items in the acquisition
module.

To reproduce the issue:
1/ Fill the pref UniqueItemFields with "barcode" and AcqCreateItem with
"placing an order"
2/ Create a new basket
3/ Create a new order
4/ Close the basket
5/ Receive items and set barcode with one already in your DB
6/ Save
7/ Nothing happen on the interface, but an error should have been added
in your Koha log file:
  Can't use an undefined value as an ARRAY reference at
  /home/koha/src/acqui/check_uniqueness.pl line 48.

Test plan:
1/ Repeat steps 1-6
2/ You should see a warning on the interface

Note that this should also happen with AcqCreateItem set to "creating an
order".

Works well, no errors.

Signed-off-by: Amit Gupta <amit.gupta@informaticsglobal.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>