[7.13](backport #26526) Add inttests for the x-pack/metricbeat on a PR/branches basis

[mergify]

This is an automatic backport of pull request #26526 done by Mergify.
Cherry-pick of 9554d72 has failed:

On branch mergify/bp/7.13/pr-26526
Your branch is up to date with 'origin/7.13'.

You are currently cherry-picking commit 9554d72ac.
  (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:   x-pack/metricbeat/Jenkinsfile.yml

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://help.github.com/articles/checking-out-pull-requests-locally/

---

Mergify commands and options

More conditions and actions can be found in the documentation.

You can also trigger Mergify actions by commenting on this pull request:

• @Mergifyio refresh will re-evaluate the rules
• @Mergifyio rebase will rebase this PR on its base branch
• @Mergifyio update will merge the base branch into this PR
• @Mergifyio backport <destination> will backport this PR on <destination> branch

Additionally, on Mergify dashboard you can:

• look at your merge queues
• generate the Mergify configuration with the config editor.

Finally, you can contact us on https://mergify.io/

And also backports #26537

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Build Cause: v1v commented: /test

• Start Time: 2021-06-29T08:39:48.125+0000

• Duration: 24 min 29 sec

• Commit: 23d1d3d

Test stats 🧪

Test	Results
Failed	0
Passed	169
Skipped	14
Total	183

Trends 🧪

💚 Flaky test report

Tests succeeded.

Expand to view the summary

Test stats 🧪

Test	Results
Failed	0
Passed	169
Skipped	14
Total	183

[v1v]

/test

[v1v]

#26486 might solve the test failures

[v1v]

/test