[Meta][Telemetry] Monitoring decoupling

[afharo]

This is a meta issue to list all the items we need to tackle to complete the decoupling process of the Telemetry & Monitoring plugins.

• Provide KibanaRequest (only when available) in the fetch method's context so collectors can scope their requests when possible ([Usage Collection] Extend the APIs provided to the fetch method #75875)
• Move Monitoring collection strategy to a collector ([Telemetry] Move Monitoring collection strategy to a collector #82638)
• Remove Monitoring's Kibana Usage collection ([Telemetry/Monitoring] Monitoring should stop collecting Kibana Usage in the .monitoring indices #83521)
• Remove the parameter timestamp in /api/telemetry/v2/clusters/_stats (Remove the parameter timestamp in /api/telemetry/v2/clusters/_stats #83625)
• Change the behaviour of telemetryCollectionManager to use this X-Pack strategy as a replacement of the OSS strategy (telemetryCollectionManager to use X-Pack strategy as a replacement of the OSS strategy #83622)
• 👆 once finished: Get license only in X-Pack strategy (Kibana logs license contains unrecognized parameters on OSS logs #82963)
• Update the remote telemetry indexer to enrich documents based on the different collection sources (https://github.com/elastic/telemetry/issues/454)

[elasticmachine]

Pinging @elastic/kibana-telemetry (Team:KibanaTelemetry)

[afharo]

Closing this issue as all the Kibana-related work is complete. The changes for the Remote Telemetry Service will be tackled on its own separate issue

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)