fdo#75256 Improve sifr icontheme

Modified apply and cancel, new ok, test for rulerrows

Change-Id: Ib5255a106390c72bb66bdd4d40e54fc0b33bb264
Reviewed-on: https://gerrit.libreoffice.org/12522
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>