Bug 32256: Display barcodes not checked out in batch

Bug 32256: Display barcodes not checked out in batch

This patch encourages the user to check out certain items individually if they fail to be checked out in a batch.

This way they will be presented with more useful error messages.

To test:

1 - Enable BatchCheckouts, select nothing in BatchCheckoutsValidCategories
2 - Find three barcodes
3 - log into SCO with a user in category Patron, paste the barcodes separated by newlines and submit. confirm one item is succcessfully checked out and the other two barcodes are listed in the pop-up, encouraged to try checking out individually.
4 - select Patron in BatchCheckoutsValidCategories
5 - log into SCO with your Patron user again, confirm you can check out multiple items at a time

Signed-off-by: Andrew Fuerste Henry <andrewfh@dubcolib.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Andrew Fuerste Henry <andrewfh@dubcolib.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>