ofz#7469 leak of SdrObject owned by SvxShape

SvxShape::InvalidateSdrObject is called and mpSdrObjectWeakReference
is reset. HasSdrObjectOwnership is only true if HasSdrObject is true
and HasSdrObject is true only if mpSdrObjectWeakReference is set.

So if mpSdrObjectWeakReference is reset in Invalidate when HasSdrObjectOwnership
is true, the shape becomes inconsistent

Change-Id: I0031c0dac33923367a2f73fcb8fe2eeb88a08db9
Reviewed-on: https://gerrit.libreoffice.org/54368Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

svx/source/unodraw/unoshape.cxx

@@ -247,6 +247,9 @@ void SvxShape::InvalidateSdrObject()
         EndListening(GetSdrObject()->getSdrModelFromSdrObject());
     }
 
+    if (HasSdrObjectOwnership())
+        return;
+
     mpSdrObjectWeakReference.reset( nullptr );
 };