This converts the public `uiItemFullR` function to an object oriented API (an overload of `uiLayout::prop`), matching the python API. This reduces the difference between the C++ API with the python version, its also helps while converting code from python to C++ code (or vice-versa), making it almost seamless. Part of: #117604 Pull Request: https://projects.blender.org/blender/blender/pulls/138683