Notification deduplication for Unified Alerting

[justinbwood]

Per the AWS Managed Grafana docs on migrating classic alerts to Grafana alerting, multiple notifications are sent when using Grafana-managed alerts.

I would like to see Grafana's high availability alerting enabled so that notifications are properly deduplicated, as it's a bit frustrating to receive Slack notifications in triplicate when using Unified Alerting.

Thanks!