Bug 25727: Upgrade the Select2 JS lib to version 4

Bug 25727: Upgrade the Select2 JS lib to version 4

In order to benefit from the last feature of Select we should upgrade to the version 4.
For instance it adds the ability to dynamically create new entries

https://select2.org/tagging

Test plan:
Confirm that there is no visible regression on dropdown list with select2
Like edit a bibliographic records, and the items.

Sponsored-by: Orex Digital

Signed-off-by: Owen Leonard <oleonard@myacpl.org>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>