MNT: automatic issues for nightly failures are broken

[neutrinoceros]

Bug report

Bug summary

The change introduced in #4560 is apparently broken, see https://github.com/yt-project/yt/actions/runs/6715141128/job/18249749179

I'm going to prioritise fixing the failing tests over this, but I'll circle back to this infrastructure issue when I'm done.