[8.0](backport #29695) Support running multiple log groups in cloudwatch input

[mergify]

This is an automatic backport of pull request #29695 done by Mergify.

---

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.com

[botelastic]

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

[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

• Start Time: 2022-01-25T15:16:46.125+0000

• Duration: 143 min 1 sec

• Commit: 9a2767a

Test stats 🧪

Test	Results
Failed	0
Passed	20855
Skipped	797
Total	21652

💚 Flaky test report

Tests succeeded.

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

• /package : Generate the packages and run the E2E tests.

• /beats-tester : Run the installation tests with beats-tester.

• run elasticsearch-ci/docs : Re-trigger the docs validation. (use unformatted text in the comment!)