Bug fix - GroupBy.describe produces inconsistent results for empty datasets
- [x] closes #41575
- [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
- [x] 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.

I close this since I stuck this for long time. I get simpler task. Thank for review. Thank for review !!! @jreback - good here? ok. Currently, I do not have ideas. I will try it.  @jreback

> umm this seems a lot special cases here - this already dispatches to describe which should be able to handle empties

This dispatches to DataFrame.describe via _python_apply_general which doesn't call the function when the frame is empty. @jreback - gentle ping. See my comment immediately above. will look

@weikhor can u merge master thanks @weikhor 