fdo#80422 check only one radio button in a group

Change-Id: Ibf1ed3d33d8b2c7da4eee26943da0c09647f4bff
(cherry picked from commit 012003e4681736083f6d3f987a69011ef0200ddc)
Reviewed-on: https://gerrit.libreoffice.org/9872
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>