CLN: Don't intercept NotImplementedError in _cython_transform
- [ ] closes #xxxx (Replace xxxx with the GitHub issue number)
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Ref: https://github.com/pandas-dev/pandas/pull/49665#discussion_r1024528347

The one place in groupby where there is `raise NotImplementedError` is in `_reconstruct_ea_result`. This is not hit by tests.

cc @jbrockmendel
lgtm. is this not user facing at all / worth a whatsnew? > lgtm. is this not user facing at all / worth a whatsnew?

This was changed from raising NotImplementedError to a TypeError in #49665. So this PR is really just reverting that change.