Remove visual noise from accessibility

Change-Id: I876e5c4d1991b35c1dc2cea709d8a2ddf781b012
Reviewed-on: https://gerrit.libreoffice.org/8225
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>