chore: update elastic-agent-libs to v0.18.8

[mauri870]

Proposed commit message

This PR updates elastic-agent-libs to the most recent version.

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.

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @mauri870? 🙏.
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-8./d is the label to automatically backport to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.

[mauri870]

Test failures are related to a breaking change in libs.
Fixed in elastic/elastic-agent-libs#283.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[strawgate]

@mauri870 I have merged a change to agent-libs for improved warning logging during SSL handling that I would love backported as well, would you be open to carving a version that includes elastic/elastic-agent-libs#285 (already merged) and bumping to that version in this PR? So that we avoid doing bumping + backports twice for the lib update

[cmacknz]

Quick request changes since I approved without realizing the changelog is going in the wrong place.

[mauri870]

I have merged a change to agent-libs for improved warning logging during SSL handling that I would love backported as well, would you be open to carving a version that includes elastic/elastic-agent-libs#285 (already merged) and bumping to that version in this PR? So that we avoid doing bumping + backports twice for the lib update.

I just tagged v0.18.8 in libs to include your change.

[mauri870]

/test

[mauri870]

/test

[cmacknz]

Thanks, will approve once CI is passing.

[mauri870]

Thanks, will approve once CI is passing.

I finally got a green CI! Just waiting on your approval. Thanks!