[Search] Unskip partial results Serverless tests

[davismcphee]

Summary

This PR unskips the partial results Serverless tests. I ran 100x flaky test runs against each project type to confirm they should no longer be flaky.

Flaky test runs:

• x100 (.only): https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3114
• x100 Search: https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3121
• x100 O11y: https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3147
• x100 Security: https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3156

Resolves #165563.
Resolves #165612.
Resolves #165763.

Checklist

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[jughosta]

Suggested change

	// TODO: Serverless tests require login first
	// Serverless tests require login first

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 6308c2d

Metrics [docs]

✅ unchanged

History

• 💛 Build #159348 was flaky 4cb930c
• 💛 Build #159312 was flaky 57b6bbe
• 💛 Build #158961 was flaky 7a575ba
• 💔 Build #158947 failed 43f2beb

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @davismcphee