Update the bundled HarfBuzz to 0.9.23

Change-Id: Ic00a4e6a4dd22bece541d822db395a92fc835e61
Reviewed-on: https://gerrit.libreoffice.org/6628
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>