BUG: SeriesGroupBy apply wrong name
- [x] closes #46369
- [x] [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).
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

@ma3da - can you merge main. Failure is unrelated. Will need an approval from @jreback to move forward looks good can merge on green Thanks @ma3da!