Bug 35013: Font Awesome icons broken in self checkout and self checkin

Bug 35013: Font Awesome icons broken in self checkout and self checkin

This patch updates the way Font Awesome icon assets are included on the
self checkout and self checkin pages. This change should have been made
during the upgrade to Font Awesome 6 (Bug 32910).

To test, apply the patch and make sure both SelfCheckInModule and
WebBasedSelfCheck system preferences are enabled.

- Go to the self checkout module (/cgi-bin/koha/sco/sco-main.pl) and log
  in.
- Check that Font Awesome icons are working: You should see an
  information icon by the "Help" link in the header, and a check mark
  icon in the "Finish" button.
- Click the help link to confirm that the icon appears there too.
- Go to the self checkin module (/cgi-bin/koha/sci/sci-main.pl).
- In the header you should see the information icon by the help link and
  an icon with the "Log out" link too.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>