BUG, TST, DOC: fix core.missing._akima_interpolate will raise AttributeError
- [x] closes #33426 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Wasn't sure if this warranted a whatsnew entry since its mostly code cleanup