Bug 25014: Fix capitalization for "Call Number" in staff and OPAC sort options

Bug 25014: Fix capitalization for "Call Number" in staff and OPAC sort options

There are some ocurrences of "Call Number" in the sort option lists in
staff and OPAC. The patch changes them to "Call number".

To test:
- Check the sort option list in staff and OPAC for the typo
- Apply patch
- Verify it's now all corrected

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>