Bug 38188: fix populating the borrowenumberlist from patron_search_selections

Bug 38188: fix populating the borrowenumberlist from patron_search_selections

This patch fixes the issue of populating the borrowernumberlist from patron_search_selections.
Adding borrowernumbers to the textarea randomly fails because the textarea is populated with the html() function.

To test:
1) Go to the patron search
2) Select a few patrons
3) Click on the "Batch patron modification" button
4) Use browsers back button to go back to the patron search
5) Find patron_batchmod_form from browser inspector, open it.
6) Check that between the <textarea> tags, there are the borrowernumbers of the selected patrons.
7) Apply the patch
8) Repeat steps 1-6
9) Check that <textarea> tags are not populated with the borrowernumbers of the selected patrons.
10) Remove the display:none from the textarea and check that the borrowernumbers are populated there.

Sponsored-by: Koha-Suomi Oy
Signed-off-by: Michelle Spinney <mspinney@clamsnet.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>