TST: Upcoming dependency test failures

[github-actions]

The weekly build with future dependencies has failed. Check the logs
https://github.com/yt-project/yt/actions/runs/8258849295

[neutrinoceros]

So, this one is actually not just bleeding edge CI: these new failures are also seen in regular CI and due to the release of pytest 8.1.1

One failure is genuine and resolved in #4849. The other one seems like a pytest bug, reported as pytest-dev/pytest#12113. If it's not addressed soon we can just pin pytest somehow in the mean time.

[neutrinoceros]

The immediate issue is fixed via #4853.