Triage Service exceptions: validation error (/origins)

The listed users and repositories cannot be searched either because the resources do not exist or you do not have permission to view them.

It is likely that this is not something we want to be logging as an exception, but I am not certain what is the expected outcome.

```
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 "Validation Failed"
```