Bug 21184: Replace C4::Items::GetBarcodeFromItemnumber calls

Bug 21184: Replace C4::Items::GetBarcodeFromItemnumber calls

Those calls to C4::Items::GetBarcodeFromItemnumber can be replaced with
    my $barcode = Koha::Items->find($itemnumber)->barcode;
But if we are not sure that the item exists, we should test the return
of ->find before ->barcode

Test plan:
- Edit an item
- Check an item in

- Test SIP - I do not really know how to trigger that code, apparently
misc/sip_cli_emulator.pl does not deal with holds. Any ideas?

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>