[Move @kbn/config-schema to server] dashboard

[afharo]

Summary

Part of #189476.

We want to avoid @kbn/config-schema from leaking to the browser, and config.ts should be part of the server logic.

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: d221f78

Metrics [docs]

✅ unchanged

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

cc @afharo