[ui, ci] Ember Exam failures should cause overall test failures

[philrenaud]

Description

Noticed that failing ember-exam tests were still yielding green checkmarks (see ember exam in https://github.com/hashicorp/nomad/actions/runs/12143968210/job/33862207314)

This moves the continue-on-error declaration out of the sub block and:

1. allows all tests in a partition to run to completion, even if one errors (up to 30 minutes)
2. has an explicit "Did something fail?" check step to throw the wider failure.

This builds on the work done in #24555

[gulducat]

I have questions! (because github actions can be quite confusing)

[gulducat]

🙄

[philrenaud]

This is because of

    paths:
      - "ui/**"

But I'm going to try to make this workflow file part of that, too.

[gulducat]

if we're checking the exam step's outcome specifically, do we need "Express timeout failure" above?

also, if you exit 1 here, the Upload step below wouldn't run. presumably you'd want the test results even if something failed?

but also, does continue-on-error at the job level, moved up to line 39, mean that all steps are continued, so this exit 1 would be ignored just like any error that yarn exam might have spit out?

I don't recall exactly the nuances of when which type of results are skipped, and I don't think I've done a job-level continue-on-error... if you're not sure either, I'd suggest making a little repo that's just for testing github actions, and creating little toy workflows so you can iterate more quickly. I suppose you could do that in a branch in this repo, but I like to do it in branches in my own lil experiment repo.

[philrenaud]

also, if you exit 1 here, the Upload step below wouldn't run. presumably you'd want the test results even if something failed?

I think probably I wouldn't want to upload the results in that case, actually; the point of uploading partition results outside of the running test step is to do look-backs and measure test timing, etc.

Although: if I also wanted to measure flakiness, I guess I would still want to upload things if there was a failure.

I think I need to think about this a bit more.