Bug 35044: Update: Order baskets

Bug 35044: Update: Order baskets

Test plan, k-t-d:

Preparation: Create additional fields for table 'aqbasket':
2 text fields, one repeatable, one not-repeatable
2 AV fields, one repeatable, one not-repeatable

1) Add a new basket, visit:
/cgi-bin/koha/acqui/basketheader.pl?booksellerid=1&op=add_form
2) Fill in name and all additional fields, click the '+New' and 'Clear'
   links,  hit 'Save'
3) Notice the basket screen shows repeated fields separated by comma.
4) Notice that only non-null additional fields labels are shown.
5) Edit the basket. Notice all fields are shown as expected.

Additional testing:

Having a repeatable field with multiple instances, go back to the
additional fields configuration and make the additional field
non-repeatable again. Edit the basket again. Notice the multiple text
instances are still shown, but the '+New' link no longer shows.
You're able to remove existing multiple instances, but unable to add new
ones, this is because the field is no longer repeatable.

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>