Make instance's editable children use warning color instead of disabled color

editor/scene_tree_editor.cpp

@@ -229,7 +229,7 @@ bool SceneTreeEditor::_add_nodes(Node *p_node, TreeItem *p_parent, bool p_scroll
 		}
 	} else if (part_of_subscene) {
 		if (valid_types.size() == 0) {
-			item->set_custom_color(0, get_theme_color(SNAME("disabled_font_color"), SNAME("Editor")));
+			item->set_custom_color(0, get_theme_color(SNAME("warning_color"), SNAME("Editor")));
 		}
 	} else if (marked.has(p_node)) {
 		String node_name = p_node->get_name();