BUG: inspect.getmembers(Series)
Make `inspect.getmembers(Series)` work, previously raised an `AbstractMethodError`.

xref: #38740


Note there was quite some discussion about this on https://github.com/pandas-dev/pandas/pull/31549 (it is also reported as a bug in python itself), and in the and this was fixed for `_constructor_expanddim` differently in https://github.com/pandas-dev/pandas/pull/33628

I don't care much about *how* it is folved, but probably good to be consistent for `_constructor_expanddim` and `_constructor_sliced` ?

> note we backported the other issue. ok for this too.

I would just leave it for 1.3 (it's not a regression like the other issue). You never know how some subclass might be using this method (or relying on the exact error class)

 > I would just leave it for 1.3 (it's not a regression like the other issue). You never know how some subclass might be using this method (or relying on the exact error class)

makes sense. > I don't care much about *how* it is folved, but probably good to be consistent for `_constructor_expanddim` and `_constructor_sliced` ?

I've made a new version, where they're the same: `_constructor_sliced`  is only for `DataFrame` (it doesn't make sense for `Series`) and `_constructor_expanddim` is only available on `Series` (doesn't make sense for `DataFrame`, now that NDFrame higher than 2 is gone).
 Ping. thanks @topper-123 