[FEATURE] Notification when alert is market as completed or acknowledged

[jowg-amazon]

Is your feature request related to a problem?
Currently, alerting only supports alerts based on trigger conditions, which, when true, mark the alert as active. However, when the alert is no longer active, it transitions into a completed or acknowledged state without generating any notification to the user that the alert has been completed or acknowledged.

What solution would you like?
Ability to configure a detector in a way so that when the alert is completed/acknowledged, it triggers a notification to a specified channel.

What alternatives have you considered?
A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?
Add any other context or screenshots about the feature request here.