Such document access should be validated, specifically if it's
called from accessibility.

Change-Id: I67fa14c7fb1bf3885fc009428b981149f3f448fb
Reviewed-on: https://gerrit.libreoffice.org/45978Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
(cherry picked from commit 7265e75f)
Reviewed-on: https://gerrit.libreoffice.org/45979Tested-by: Jenkins <ci@libreoffice.org>