[e2e] Add tests for agent.monitoring to otel format

[khushijain21]

What does this PR do?

It adds tests for comparing docs ingested by agent.monitoring vs otel.yml

Checklist

• I have read and understood the pull request guidelines of this project.
• 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/fragments using the changelog tool
• I have added an integration test or an E2E test

How to test this PR locally

Related issues

• Closes #4877

[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 monitoringdocs upstream/monitoringdocs
git merge upstream/main
git push upstream monitoringdocs

[mergify]

This pull request does not have a backport label. Could you fix it @khushijain21? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-./d./d is the label that automatically backports 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.

[khushijain21]

Waiting on #6837 for this PR to be ready

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[michel-laterman]

I have nitpicks regarding the test, the test is also failing,

I think you're missing some ignore fields, for example the buildkite output shows differences with the cloud.instance.id and name (among other fields):

+- 	"cloud.instance.id":       string("6692864320899608549"),
--
  | ++ 	"cloud.instance.id":       string("5902608334348578789"),
  | +  	"cloud.instance.name": strings.Join({
  | +  		"bk-agent-prod-gcp-1740034313",
  | +- 		"605048021",
  | ++ 		"705811855",
  | +  	}, ""),

[michel-laterman]

Suggested change

	findCtx, findCancel := context.WithTimeout(context.Background(), 10*time.Second)
	findCtx, findCancel := context.WithTimeout(ctx, 10*time.Second)

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube