and drop Dialog::GetResult as a consequence

Change-Id: Id80a9dc1eab1a23daf4489719b3bafec976bb048
Reviewed-on: https://gerrit.libreoffice.org/62700
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>