[9.1] (backport #10203) Check for config processing errors in coordinator unit tests

[mergify]

What does this PR do?

Adds checks for config processing errors in coordinator unit tests. These tests have been flaky in the past, and the lack of diagnostic information makes it difficult to find the root cause.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have made corresponding change to the default configuration files
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added an entry in ./changelog/fragments using the changelog tool
• [ ] I have added an integration test or an E2E test

Related issues

• Relates [Flaky Test]: TestCoordinatorPolicyChangeUpdatesRuntimeAndOTelManager – empty policy should be acknowledged #10105

---

This is an automatic backport of pull request #10203 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 0ba2ea6 has failed:

On branch mergify/bp/9.1/pr-10203
Your branch is up to date with 'origin/9.1'.

You are currently cherry-picking commit 0ba2ea683.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   internal/pkg/agent/application/coordinator/coordinator_unit_test.go

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elasticmachine]

💔 Build Failed

• Buildkite Build
• Commit: abae4c2

Failed CI Steps

• check-ci
• Unit tests - Ubuntu 22.04
• Unit tests - Ubuntu 22.04
• Unit tests - Ubuntu 22.04 with requirefips build tag
• Unit tests - Ubuntu 22.04 with requirefips build tag
• Unit tests - fips140=only Ubuntu 22.04
• Unit tests - fips140=only Ubuntu 22.04
• Unit tests - Ubuntu 22.04 ARM64
• Unit tests - Ubuntu 22.04 ARM64
• Unit tests - Windows 2022
• Unit tests - Windows 2022
• Unit tests - Windows 2016
• Unit tests - Windows 2016
• Unit tests - macOS 15 ARM
• Unit tests - macOS 15 ARM
• Unit tests - Windows 10
• Unit tests - Windows 10
• Unit tests - Windows 11
• Unit tests - Windows 11

History

cc @swiatekm