Remove the red workflows from CI

We're running a lot of different workflows on PRs to this repo now. I find it extremely confusing to have red runs on PRs. Also, I think it promotes the expectation that it's OK for CI on PRs to be red.

If we expect and want to keep expecting a failure of some workflow, I think we should catch such failure in the workflow and report workflow success on that failure, and workflow failure otherwise. This would send a clear signal to the contributors: 🟢 - the workflow reached an expected result (be it success or failure), 🔴 - the workflow reached an unexpected result (you have to look into it).

cc @laurentsenta