KDE4: Report correct check and radio item sizes

Use the correct sizs from the current style.

(cherry picked from commit ab1f5eab4830f00dbbd7c883b98b59975ecd3bb1)

Change-Id: I0a5307989ba8172b011eafa04d00fa3fb4b9919c
Reviewed-on: https://gerrit.libreoffice.org/8703
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>