Bug 24665: (QA follow-up) Fix selection default

Bug 24665: (QA follow-up) Fix selection default

This patch updates the html_helper for the cash register selection block
to remove the 'empty option' such that it can be correclty set for each
select case and updates all existing cases where we used the process
block previously to include the relevant blank option '-- Select an
option --', '-- None --', 'Library default' and finally the new '-- All
--' options introduced with this bug.

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