Fix broadcast alert not triggering PagerDuty
Fix broadcast alert not triggering PagerDuty

We previously decided against this [^1] but the lambda alerts are
not a replacement for this one.

Even if both sets of alerts go off, we expect PagerDuty to aggregate
them into a single notification.

[^1]: https://github.com/alphagov/notifications-api/commit/65c21f694c98ea838abab6dd6d01c4cb07aa8ca3

alphagov/notifications-api,alphagov/notifications-api