BUG: Series.to_dict does not return native Python types
- [x] xref #25969
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

This resolves the issue of return types from `to_dict`. #25969 also discusses return types from `.items()`, which relates to an outstanding NumPy issue numpy/numpy#14139, and I don't address that part here atm