BUG: DataFrame.apply axis=1 for str ops with no axis argument
- [x] closes #39211
- [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


thanks @rhshadrach pls create an issue (or PR!) for re-orging the apply tests :->