Bug 29215: (bug 3137 follow-up) Fix guarantor block toggle

Bug 29215: (bug 3137 follow-up) Fix guarantor block toggle

The guarantor template must be kept hidden, always.

Test plan:

Edit a patron with a guarantor, click the legend of the "patron
guarantor" block and confirm that the template is not shown

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit b9d34c16e9b0ac83e055356c3680d87724528b57)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>