[Stack Monitoring] Check monitoring.ui.enabled effects on monitoring features

[tonyghiani]

📓 Summary

Kibana version: 8.4.3

The monitoring.ui.enabled configuration, as stated in the kibana documentation, states

Set to false to hide Stack Monitoring. The monitoring back-end continues to run as an agent for sending Kibana stats to the monitoring cluster. Defaults to true.

However, while investigating an issue, we realized that when it is set to false it also hides the monitoring rules, even if not disabling them.

We should further investigate which features this flag controls and if this is a bug that needs to be worked out.

✔️ Acceptance criteria

• Identify all the features affected by the monitoring.ui.enabled flag.
• Verify whether any identified feature is an undesired side effect or a product choice.

[elasticmachine]

Pinging @elastic/infra-monitoring-ui (Team:Infra Monitoring UI)