Bug 20074: Fix hidden value in auth_subfields_structure

Bug 20074: Fix hidden value in auth_subfields_structure

The template included an else branch where a value not equal to 0 or -5
was interpreted as 0 (Show all).
This effectively converted hidden values 1 and 8 to 0.
This patch removes that else branch.

Test plan:
Toggle a authority field between Hide all and Show all. Check what happens.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>