fdo#56980 drop cached shape engine on invalidation

Change-Id: I9591375e1f7d1b6f69ca9a39add52a94ac852c7f

svx/source/svdraw/svdoashp.cxx

@@ -3211,6 +3211,7 @@ bool SdrObjCustomShape::doConstructOrthogonal(const ::rtl::OUString& rName)
 void SdrObjCustomShape::InvalidateRenderGeometry()
 {
     mXRenderedCustomShape = 0L;
+    mxCustomShapeEngine = 0L;
     SdrObject::Free( mpLastShadowGeometry );
     mpLastShadowGeometry = 0L;
 }