fdo#73436 Let SdXImpressDocument handle css.drawing.* requests directly

...instead of handing off to base class, so that potential wrapping in SdXShape
(in create) is not skipped.

Change-Id: I57fb10ef478688a5a0c1c3c736efbd55a7172423
(cherry picked from commit a675873cb2bad78a5da3e3b089bebf01ca60f898)
Reviewed-on: https://gerrit.libreoffice.org/7405
Reviewed-by: Eike Rathke <erack@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Andras Timar <andras.timar@collabora.com>