This replaces `uiItemFullOMenuHold_ptr`, `uiItemFullR_with_popover`, `uiItemFullR_with_menu`, `uiItemPopoverPanel`* and `uiItemSpacer` API with methods following uiLayout refactors and the Python API. Part of: #117604 Pull Request: https://projects.blender.org/blender/blender/pulls/141050