Bug 25012: Fix class on OPAC view link in staff detail page

Bug 25012: Fix class on OPAC view link in staff detail page

Probably a copy & paste error: the OPAC view link on the staff
detail page currently has the class succeeding_entry_note.

This patch changes it to opac_view to allow for independent
styling of the link.

Note: The link will only be visible when OPACBaseURL is set.

To test:
- Use the element inspector or check the source code for
  the class used on the OPAC view link on the staff detail page
- Apply patch
- Repeat and verify that the class has changed to opac_view

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