Bug 34204: Fix koha-shell under debian 12

Bug 34204: Fix koha-shell under debian 12

In Debian 12/Bookworm:
root@kohadevbox:koha$ koha-shell kohadev
This account is currently not available.

This is because /etc/passwd has /usr/sbin/nologin as shell, which is coming from the --disabled-login param we passed to adduser in koha-create.

Looks like a bug has been fixed in adduser, because we didn't have this behavior in bullseye.

Context:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=625758#72

"""
- change and document (adduser(8)) that --disabled-password will behave
  like --disabled-login and additionally set the shell to
  /usr/sbin/nologin.
"""
https://salsa.debian.org/debian/adduser/-/commit/427ade7d9116af5af7baa9d0c538e14fa86560cf

Test plan:
Confirm the above and that the change makes sense.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>