[Dataset Quality] Fix flaky test for degraded fields flyout

[couvq]

Summary

This PR should fix a flaky test that was discovered after a recent serverless build. The fix is similar to this PR where assertions of UI element presence were occurring without a proper await for all the neccessary data to be loaded.

69 passing (8.0m)
--
1 failing
 
1)    serverless observability UI
Dataset Quality
Degraded fields flyout
detecting root cause for ignored fields
current field limit issues
should display increase field limit as a possible mitigation for special packages like apm app:
 
Error: expected testSubject(datasetQualityDetailsDegradedFieldFlyoutFieldLimitMitigationAccordion) to exist
at TestSubjects.existOrFail (test_subjects.ts:76:13)
at Context.<anonymous> (degraded_field_flyout.ts:967:11)
at Object.apply (wrap_function.js:74:16)

[elasticmachine]

Pinging @elastic/obs-onboarding-team (Team:obs-onboarding)

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 3c84a78

Metrics [docs]

✅ unchanged

[couvq]

Closing as we decided to skip the test in order to unblock serverless releases. Issue likely stems from how apm index mappings are handled, our test is not set up to handle this in its current state.