Bug 35126: Remove onload from opac-addbybiblionumber.pl

Bug 35126: Remove onload from opac-addbybiblionumber.pl

To test:

Case a) Adding to a new list

1. Enable virtualshelves system preference
2. Search for any record and click it
3. On the right hand side of record view, click "Save to your lists"
4. A new pop up opens.
5. Under "Add to a new list", give any name to the list
6. Under "Add to a new list", click "Save"
7. Observe popup closing
8. Observe record view page reloading

Case b) Adding to an existing list

1. Enable virtualshelves system preference
2. Search for any record and click it
3. On the right hand side of record view, click "Save to your lists"
4. A new pop up opens.
5. Under "Add to a list", select an existing list
(it can be the same as the one you created in case a, it does not matter here)
6. Under "Add to a list", click "Save"
7. Observe popup closing
8. Unlike case a, observe record view page NOT reloading

Signed-off-by: David Cook <dcook@prosentient.com.au>
Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 8cfce49d14ec38ff0fb053b0051391d55a9a341a)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit c2606618c03edcac7e3356d757fd74f320df348d)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>