[Discover] Fix failing tests due to log level badge colour changes in Borealis

[davismcphee]

Summary

This PR fixes functional tests that started failing due to changes to log level badge colours in Borealis. I'm not sure why these started failing or how the PR where it started passed CI, but based on the timeline and test file changes, it looks like it's related to #210468.

cc @tkajtoch Maybe you have some idea what's going on here?

Resolves #211174.
Resolves #211215.

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
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This was checked for breaking HTTP API changes, and any breaking changes have been approved by the breaking-change committee. The release_note:breaking label should be applied in these situations.
• Flaky Test Runner was used on any tests changed
• The PR description includes the appropriate Release Notes section, and the correct release_note:* label is applied per the guidelines

[kibanamachine]

Flaky Test Runner Stats

🎉 All tests passed! - kibana-flaky-test-suite-runner#7889

[✅] x-pack/test_serverless/functional/test_suites/observability/config.ts: 25/25 tests passed.

see run history

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 9f1ed46

Failed CI Steps

• FTR Configs #104

Test Failures

• [job] [logs] FTR Configs #104 / Fleet Endpoints fleet_setup upgrade managed package policies should upgrade managed package policies

Metrics [docs]

✅ unchanged

cc @davismcphee

[elasticmachine]

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

[elasticmachine]

Pinging @elastic/obs-ux-logs-team (Team:obs-ux-logs)