Fix monaco editor functional test service check

[davismcphee]

Summary

This PR fixes a monaco editor functional test service check that was added in #193851. The check validates that the editor updates with the correct text content, but it looks like it may run a bit too quickly sometimes before the DOM has a chance to update.

Fixes #194511.
Fixes #194482.
Fixes #194425.
Fixes #194305.

Flaky test runs:

• https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/7099

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
• Flaky Test Runner was used on any tests changed
• 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

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 1a49126

Metrics [docs]

✅ unchanged

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

cc @davismcphee

[kibanamachine]

Flaky Test Runner Stats

🟠 Some tests failed. - kibana-flaky-test-suite-runner#7099

[✅] test/functional/apps/discover/group4/config.ts: 50/50 tests passed.
[❌] x-pack/test_serverless/functional/test_suites/observability/common_configs/config.group6.ts: 28/50 tests passed.

see run history

[elasticmachine]

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

[davismcphee]

On the other hand, the failure in this flaky test run looks to be caused by the issue resolved in #195147, not the one causing these failures. Guess we won't get a clean run until one of them is merged:

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 2988ec1

Metrics [docs]

✅ unchanged

cc @davismcphee

[kertal]

LGTM 👍