[CPS] use real data for getting linked projects

[mbondyra]

Summary

Closes #238511.

Refactors the project picker into a new shared package (@kbn/cps-utils) to enable reusability across multiple consumers, and uses the real data to get Linked projects to the picker.

Changes

Architecture

• New Package: Created @kbn/cps-utils package containing the project picker component and related utilities
• CPS Manager: Added cpsManager service in the CPS plugin that fetches linked projects when running in serverless + CPS mode
• Project Routing: Extended @kbn/es-query with project routing types (ProjectRouting)

Project Picker Enhancements

• Consumer-Driven Routing: Project picker now accepts projectRouting and onProjectRoutingChange props, allowing consumers (e.g., Dashboard, Lens layers, global) to manage routing state
• Conditional Rendering: Picker only displays when CPSManager returns valid data with at least one linked project
• Testing: Added unit tests and integration tests for the project picker component

Configuration Changes

• Feature Flag Migration: Removed localStorage-based feature flag in favor of YAML configuration
• New Config Requirements: To enable CPS mode, add the following to your serverless.yml:

  cps.enabled: true
  cps.cpsEnabled: true

How to test it

• To set up CPS, make sure to use the internal doc we use for this purpose.

For now, the data in the picker should reflect what has been set up, but picker is not reactive.

[elasticmachine]

💔 Build Failed

• Buildkite Build
• Commit: ca8856d

Failed CI Steps

• Build Kibana Distribution

History

• 💔 Build #356747 failed 5288765
• 💔 Build #356733 failed ea0e415
• 💔 Build #356705 failed aad7c82
• 💔 Build #356656 failed f0ef1d3