Bug 16530: Add a new method to the Branches TT Plugin to avoid c/p

Bug 16530: Add a new method to the Branches TT Plugin to avoid c/p

We should do the same for the other check (FA exists), but cannot find a
good and quick way to implement.

Doing it this way will avoid regression later, we will no have to check
if the variable is correctly passed to the template.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>