[8.15](backport #41128) [Heartbeat] Fix linting issues introduced by auto-merge #41077

[mergify]

Proposed commit message

Fix linting issues introduced by auto-merge of #41077.

Checklist

• [x ] 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.next.asciidoc or CHANGELOG-developer.next.asciidoc.

---

This is an automatic backport of pull request #41128 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of efb563c has failed:

On branch mergify/bp/8.15/pr-41128
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit efb563c890.
  (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:   heartbeat/monitors/monitor.go
	both modified:   heartbeat/monitors/monitor_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/obs-ds-hosted-services (Team:obs-ds-hosted-services)

[mergify]

This pull request has not been merged yet. Could you please review and merge it @emilioalvap? 🙏