Bug 14805: (follow-up) fix a bug in previous code and change msg string

Bug 14805: (follow-up) fix a bug in previous code and change msg string

Previously the code didn't work if there was only one batch available for selection.
This fixes that now. Also there was a bug with wrong string showing now it's
changed to a general one, "items". I choosed the string "items" because there was
difficulties adding the plural part of the word. One cannot add just s to the end
of the word batch like you can in the case of profile.

Sponsored-by: Vaara-kirjastot
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>