Better detail in critical event notifications

Detail should probably be anything other than an empty object.
```json
{"version":"0","id":"91a68cd8-1041-0d52-8ded-1e2a7722c930","detail-type":"Scheduled Event","source":"aws.events","account":"XXXXX","time":"2023-02-15T22:50:14Z","region":"us-east-2","resources":["arn:aws:events:us-east-2:522820226885:rule/npkSpotMonitor"],"detail":{}}
```