Revert "Queue inspector tree update when changing the theme."

This reverts commit c0baec410b0617ddb36c278230f3b60da1444af6.

See comments in #70381.

editor/editor_inspector.cpp

@@ -3856,10 +3856,6 @@ void EditorInspector::_notification(int p_what) {
 			_update_inspector_bg();
 		} break;
 
-		case NOTIFICATION_THEME_CHANGED: {
-			update_tree();
-		} break;
-
 		case NOTIFICATION_ENTER_TREE: {
 			if (!sub_inspector) {
 				get_tree()->connect("node_removed", callable_mp(this, &EditorInspector::_node_removed));