CI: Clean circleci setup env file
- [x] closes #48307 (Replace xxxx with the Github issue number)
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature

#48307 is tracked by #47305. Cleaning the `setup_ev.sh` file since it's only used for this build.
Thx for this. Wasn’t aware that the issue was still open.

should we switch to mambaforge as a follow up? > should we switch to mambaforge as a follow up?

Yes, that would be a useful followup PR. Thx @mroeschke 