Triage Service exceptions: summarizeService.summarize is not a function (/harvest)

```
requests 
| where resultCode == 500
| join (
 exceptions
 ) on operation_Id 
| extend pathPrefix = extract("/(\\w+)", 0, tostring(operation_Name))
| summarize count() by  outerMessage, pathPrefix
| order by count_  desc 
| where outerMessage contains "summarizeService.summarize is not a function" 
```