fdo#74751: fix reverse base point diagram on RTL UI

Change-Id: Ib8e9f40b5576116f0220ffa70390f95b28c8bae0
Reviewed-on: https://gerrit.libreoffice.org/8200
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>