text: Title: Fix `test_regressions` tests failing in GitHub Actions
  Body: I had to mark the `test_regressions` tests with XFAIL when running the checks in CI because they are currently failing when being run in GitHub Actions. See [here](https://github.com/tpvasconcelos/ridgeplot/actions/runs/7378769595/job/20074296603) and [here](https://github.com/tpvasconcelos/ridgeplot/actions/runs/7378769595/job/20074296398). 
  
  This is probably due to small differences in output between environments (local vs. remote macOS, Windows, and Linux).
  
  The test, for reference:
  https://github.com/tpvasconcelos/ridgeplot/blob/34498e54b2381ed97ac09f182df5a40f8e4a4943/tests/e2e/test_examples.py#L30-L37
  
  Regardless of the solution, one nice feature to implement here is the ability to upload the plot artefacts that resulted in the failed tests and expose these artefacts to the relevant PR. This discussion might be useful for this: 
  - https://github.com/actions/upload-artifact/issues/50
  other references on this topic:
  - https://github.com/orgs/community/discussions/51403
  - https://github.com/djthornton1212/djthornton1212/blob/main/.github/workflows/pr-comment-artifact-url.yml
  - https://stackoverflow.com/questions/60789862/url-of-the-last-artifact-of-a-github-action-build