Fix for - Bug GVIEW11271

SMESH: Add Polyhedron by Faces - Crash

src/SMESHGUI/SMESHGUI_CreatePolyhedralVolumeDlg.cxx

@@ -109,6 +109,7 @@ class TPolySimulation{
       myPreviewActor->PickableOff();
       myPreviewActor->VisibilityOff();
       myPreviewActor->SetMapper( myMapper );
+      myPreviewActor->SetRepresentation( 3 );
 
       float anRGB[3];
       vtkProperty* aProp = vtkProperty::New();