ENH: Allow numba aggregations to return non-float64 results
- [ ] xref #44952 (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.

Could you also add a whatsnew note for 2.1? There seems to be some flakiness with the benchmarks I added.
(Wasn't able to get an error message unfortunately).

I'll let this sit for a couple of days then, but other than that it should be good to go.

EDIT: Root caused, it was a timeout in the benchs.