Fixes use after free in redo of "Create Custom Bone2D(s) from Node(s)"

Using "queue_free" on the undo of the creation of the Bone2D meant that on the redo the Bone2D was already deleted.

Replaced it with "add_do_reference", so when the Action of the undo_redo is destroyed, also destroys the Bone2D.

editor/plugins/canvas_item_editor_plugin.cpp

@@ -4805,11 +4805,12 @@ void CanvasItemEditor::_popup_callback(int p_op) {
 				undo_redo->add_do_method(new_bone, "add_child", n2d);
 				undo_redo->add_do_method(n2d, "set_transform", Transform2D());
 				undo_redo->add_do_method(this, "_set_owner_for_node_and_children", new_bone, editor_root);
+				undo_redo->add_do_reference(new_bone);
 
 				undo_redo->add_undo_method(new_bone, "remove_child", n2d);
 				undo_redo->add_undo_method(n2d_parent, "add_child", n2d);
+				undo_redo->add_undo_method(n2d_parent, "remove_child", new_bone);
 				undo_redo->add_undo_method(n2d, "set_transform", new_bone->get_transform());
-				undo_redo->add_undo_method(new_bone, "queue_free");
 				undo_redo->add_undo_method(this, "_set_owner_for_node_and_children", n2d, editor_root);
 			}
 			undo_redo->commit_action();