AffectedUsersCount: Approximate number of affected users in the given group that match the selection criteria. Users are distinguished by data in the `ErrorContext` of the individual error events, such as their login name or their remote IP address in case of HTTP requests. The number of affected users can be zero even if the number of errors is non-zero if no data was provided from which the affected user could be deduced. Users are counted based on data in the request context that was provided in the error report. If more users are implicitly affected, such as due to a crash of the whole service, this is not reflected here.