[RAM] Machine learning alerts working with cases

[XavierM]

The ML team just merged this #167998 to show alerts data in the Anomaly Explorer. During the development of this feature, we realized that these alerts can belong to different solutions like observability, security or just stack. Therefore, in the Anomaly Explorer, we would like to create a case or add to an existing case for different solutions. At this point of time, this feature is not possible because our cases are silos by solutions (security/o11y/stack). Also our alerts are silos but in a different way because security users access their rule with their own privileges but o11y/stack user are accessing this alert with the kibana user with some authentication filter on top of the alert index. We need to figure out how to remove this bottleneck in the near future to make it a seamless experience for our user.

For 8.12, We would like to make sure that our ML/stack alerts can be linked to a stack cases with no problem. For our o11y user, we will introduce the anomaly detection rule in o11y rule management page with this #170451. This will allow o11y user to create o11y cases and link these alerts there.

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)