Fix the warning message from not using the editor theme, closes #5002

tools/editor/editor_node.cpp

@@ -6275,7 +6275,7 @@ EditorNode::EditorNode() {
 	logo->set_texture(gui_base->get_icon("Logo","EditorIcons") );
 
 	warning = memnew( AcceptDialog );
-	add_child(warning);
+	gui_base->add_child(warning);