[Search][Onboarding] Empty State page endpoints

[TattdCodeMonkey]

Summary

This PR introduces two endpoints for the search_indices plugin that will be used by the start (empty state) page to determine if the user has an indices and what their permissions are.

Checklist

• Unit or functional tests were updated or added to match the most common scenarios
• Flaky Test Runner was used on any tests changed

[TattdCodeMonkey]

@elasticmachine merge upstream

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: a2d5169

Failed CI Steps

• FTR Configs #84

Test Failures

• [job] [logs] FTR Configs #84 / Cloud Security Posture Test adding Cloud Security Posture Integrations CSPM AZURE Azure Single Manual Managed Identity Azure Single Manual Workflow

Metrics [docs]

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
searchIndices	6	10	+4

Unknown metric groups

API count

id	before	after	diff
searchIndices	6	10	+4

History

• 💔 Build #229787 failed 3a7eb2d854611d0de70b598db620281b3f63d1b7
• 💚 Build #229589 succeeded c27f6d2394317cfe8ed616d59bb24182f35dc97f

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