Forward persistent notifications to the notification service

After an unattended upgrade of Home Assistant, a service (InfluxDB) wasn’t yet available during the Home Assistant startup. This triggered a persistent notification. Which I promptly missed because the whole upgrade was unattended.

How can I forward all persistant notifications to my notify.notify service?

I couldn’t figure out the appropriate trigger for my automation. The event persistent_notifications_updated doesn’t fire as far as I can see.