Bug 35044: Update: Serial subscriptions batch edit

Bug 35044: Update: Serial subscriptions batch edit

Test plan, k-t-d:

Preparation: Create additional fields for table 'subscription', visit:
/cgi-bin/koha/admin/additional-fields.pl?tablename=subscription

2 text fields, one repeatable, one not-repeatable
2 AV fields, one repeatable, one not-repeatable
2 MARC fields, one 'get' and one 'set', both non-repeatable, MARC field
942$c
Attempt to create a repeatable MARC field (get or set). Notice you're
unable to.

1) Add a new serial subscription, visit:
/cgi-bin/koha/serials/subscription-add.pl
2) Set the mandatory "Record" input (e.g. '112'). Click the 'Next' and
   press 'Ok' on the alert box.
3) Fill in all required fields and press "Test prediction pattern"
4) At the bottom, fill in all additional fields, click the '+New' and
   'Clear' links,  hit 'Save'
5) Notice the fields are shown, repeated fields are comma separated
6) Repeat steps 1-4 to create a second subscription
7) Visit serials home and hit "Search":
/cgi-bin/koha/serials/serials-home.pl
8) Check the checkboxes next to the 2 subscriptions and click "Edit
   selected serials"
9) Input some values in the additional fields section, click the '+New'
   and 'Clear' links,  hit 'Save'
10) Verify that both subscriptions now have the new values form the
    batch edit.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>