Fix monaco editor functional test service check (#195154)

## 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](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

test/functional/services/monaco_editor.ts

@@ -63,11 +63,13 @@ export class MonacoEditorService extends FtrService {
         value
       );
     });
-    const newCodeEditorValue = await this.getCodeEditorValue(nthIndex);
-    expect(newCodeEditorValue).equal(
-      value,
-      `Expected value was: ${value}, but got: ${newCodeEditorValue}`
-    );
+    await this.retry.try(async () => {
+      const newCodeEditorValue = await this.getCodeEditorValue(nthIndex);
+      expect(newCodeEditorValue).equal(
+        value,
+        `Expected value was: ${value}, but got: ${newCodeEditorValue}`
+      );
+    });
   }
 
   public async getCurrentMarkers(testSubjId: string) {