[Logs UI] link-to node logs routes depend on the deprecated graphql source configuration API

[weltenwort]

Problem description

The logs/link-to/{container,host,pod}-logs routes still read the corresponding fields from the graphql-based source configuration API, because these fields are not available from the new plain JSON API.

Possible solutions

Two possible solutions come to mind:

1. Add the three required field configurations to the response of the new log source configuration API.
2. Remove the dependency of these fields by hard-coding them in the link-to redirects. This would break backwards-compatibility.

[elasticmachine]

Pinging @elastic/logs-metrics-ui (Team:logs-metrics-ui)