ENH: add ignore index to DataFrame / Series.sample
- [x] closes #38581
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Picking up #38594. Left in 1.3 for now since all comments were addressed except small typing issues and seems like a nice enhancement, but let me know if it should be moved.