Deletes a monitor. CloudZero stops evaluating it, and it no longer appears in List monitors; Get monitor returns 404 for it. Its incidents drop out of List incidents, but Get incident still returns them, with monitor_id set to null.
Deleting a monitor that is already deleted returns the same response, so a retried request is safe. Returns 403 for monitors created by CloudZero, which cannot be deleted; pause them with Update monitor instead. Returns 404 if the monitor does not exist or belongs to another organization.