TST: DataFrame.interpolate(axis='columns') throws exception while DataFrame.interpolate(axis=1) not (#25190)
Make sure that DataFrame.interpolate allows setting having "columns" or "index" as the `axis` argument.

I included the `whatsnew` entry as well. However, since the bug was already fixed in v1.0.0, it might be reasonable to just drop it. I leave it to the reviewer's discretion, that's why I've put it in a separate commit.

- [x] closes #25190
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry
