Bug 18127: Add batch modified records to an existing list

Bug 18127: Add batch modified records to an existing list

To test:
1) Start by having no (zero) lists
2) Go to Tools -> Batch record modification
3) Go through the batch record modification process, confirm everything
works as normal and there is a link to do a new batch record
modification at the end
4) In another tab, go to Lists and create a new list
5) Go back to the first tab and start a new batch modification process
6) At the end of the process, there should be a new option to add
modified records to an existing list
7) Select a list from the dropdown and confirm you are able to save your
modified records to the list as expected
8) Start a new batch modification process, this time for authorities
records
9) At the end confirm there is no option to add modified records to a
list, because authorities cannot be added to lists

Sponsored-by: Catalyst IT
Signed-off-by: Jessica Zairo <jzairo@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>