b36e5b4b06
This renames `UI_block_layout` API as `blender::ui::block_layout`, following uiLayout refactors. This function now returns a layout reference instead of pointer, this changes applies this return type where the layout can be used as such reference. Changes includes the use of `blender::ui::LayoutDirection` and `blender::ui::LayoutType` as typed enum parameters. Part of: #117604 Pull Request: https://projects.blender.org/blender/blender/pulls/141401