Allow Standard+ monitoring cluster to show stack monitoring data from any license monitored cluster

[ravikesarwani]

Stack monitoring UI should show data from any monitored cluster if its own license is Standard+.

Multi-stack monitoring is available on Standard+ license. It is not available on "FREE AND OPEN - BASIC" license.
https://www.elastic.co/subscriptions/ & https://www.elastic.co/subscriptions/cloud
Currently the monitoring cluster SM UI code validates the license for all the monitored clusters and shows the data for itself and any clusters that are Standard+ license. It will not show monitored cluster that are on Basic even if its own license is Standard+.

This worked fine when all clusters were in self-managed or Cloud environment. A single license/subscription was usually applied to all the clusters.

In hybrid world it would be a great way (IMO) to introduce customers to Elastic cloud for monitoring use case and get them hooked to it and potentially get more workloads moved to cloud over time. We are getting paying customer and introducing them to the benefits of Elastic cloud.

[elasticmachine]

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

[elasticmachine]

Pinging @elastic/stack-monitoring (Team:Monitoring)