Fix CSGMesh undo not refreshing gizmo

(cherry picked from commit 4311c2f66e4a1c9b7b77e8d3cdce4be8fa3ec7fa)

modules/csg/csg_shape.cpp

@@ -911,7 +911,7 @@ void CSGMesh::set_mesh(const Ref<Mesh> &p_mesh) {
 		mesh->connect("changed", this, "_mesh_changed");
 	}
 
-	_make_dirty();
+	_mesh_changed();
 }
 
 Ref<Mesh> CSGMesh::get_mesh() {