[8.15](backport #40565) [metricbeat][system/process, system/process_summary]: mark module as healthy if metrics are partially filled

[mergify]

• Bug

Proposed commit message

• If metrics are partially available for system.process and system.process_summary, do not mark metricset as degraded.
• Instead, keep it healthy and display the message

Checklist

• 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.

How to test this PR locally

• Clone from this branch
• Do mage package from x-pack/agentbeat
• Run elastic agent with new agentbeat binary
• Run as unprivileged mode, and run elastic-agent status --output=json
• You should see HEALTHY state and error message displayed

Related issues

• Closes [Elastic Agent] The system process metricsets should not report as degraded when metrics are partially collected #40542

Use cases

Screenshots

---

This is an automatic backport of pull request #40565 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 1f033c9 has failed:

On branch mergify/bp/8.15/pr-40565
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit 1f033c9eed.
  (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)

Changes to be committed:
	modified:   CHANGELOG.next.asciidoc
	modified:   metricbeat/mb/event.go
	modified:   metricbeat/module/system/process/process.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   metricbeat/mb/module/wrapper.go
	both modified:   metricbeat/module/system/process_summary/process_summary.go

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

[botelastic]

This pull request doesn't have a Team:<team> label.

[mergify]

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

[mergify]

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

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b mergify/bp/8.15/pr-40565 upstream/mergify/bp/8.15/pr-40565
git merge upstream/8.15
git push upstream mergify/bp/8.15/pr-40565

[mergify]

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

[rdner]

@VihasMakwana could you help me to resolve conflicts?

[VihasMakwana]

@rdner actually, I dont think we need this. This is a follow-up PR of #40443

@cmacknz closed #40443. See #40443 (comment)