filebeat - stop warning under elastic-agent

[andrewkroh]

Proposed commit message

This message is being logged excessively when running under Elastic Agent. It's not relevant because Fleet manages pipelines. So disable it.

Filebeat is unable to load the ingest pipelines for the configured modules because the Elasticsearch output is not configured/enabled. If you have already loaded the ingest pipelines or are using Logstash pipelines, you can ignore this warning.

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.

Screenshots

(Yes, there are problems in that deployment and Filebeat is restarting a lot, but this message doesn't need to be logged.)

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @andrewkroh? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[cmacknz]

Thanks!

[elasticmachine]

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• Start Time: 2023-09-22T16:55:02.741+0000

• Duration: 70 min 42 sec

Test stats 🧪

Test	Results
Failed	0
Passed	8257
Skipped	753
Total	9010

💚 Flaky test report

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