fdo#76633: writerfilter RTF import: disappear the rectangle shapes on images

If the shape properties are inside \picprop destination, don't set
shapeType.

(regression from 9f1f7199736e2ae07b34849ba66f61a1ef5782e8)

Actually this does not fix the root cause, this is just a work-around,
the extra shape is still inserted but it's invisible now.

Change-Id: I6cf093de2a5657533f393863ed8010ae083bec16
fdo#76633: writerfilter: RTF import: do not leak the XShape of image

RTFSdrImport::resolve() is called for \picprop and creates an XShape
that is stored in RTFSdrImport::m_xShape and also
DomainMapper_Impl::m_aPendingShapes;
later RTFDocumentImpl::resolvePict() completely ignores that XShape
and creates a new one, which is also inserted in the document;
the first XShape is effectively leaked.

Try to avoid that by re-using the exising m_xShape in resolvePict().
Not sure if there are any problems with doing this, it's all a bit
confusing.

Change-Id: I98456242acb0766f547eb8f7d877f51d53323f3a