CLN: remove abc.abstractproperty from code base
- [x] xref #25725 
- [x] xref #26165

While doing #26165 I discovered some uses of ``abc.abstractproperty`` in the codebase. This propery was deprecated in Python 3.3 and superseeded by using ``abc.abstractmethod`` and ``property`` together instead (see [python abc.abstractproperty docs](https://docs.python.org/3.7/library/abc.html#abc.abstractproperty)). I've therefore removed the uses of ``abc.abstractproperty`` from the code base.
