BUG: set_levels set wrong order levels for MutiIndex
- [ ] closes #33420
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Added parameter that allows user to reset codes
If there's a better way to update the codes, please let me know! @jreback Thanks for getting back to me! Sorry if I misunderstood the issue, but I originally believed that set_levels should effectively reassign the index automatically. I do realize now that adding a parameter to the method isn't necessary since the user can reassign the index themselves. Please let me know what your thoughts are on my original understanding! closing as this is an internal implementation detail.