Host unable to write diagnostics events to table storage if app is configured with managed identity

[nzthiago]

I had a function app that triggers from Service Bus. The app has service identity configured and the app and has the following role assignments:
Storage Blob Data Owner
Storage Table Data Contributor
Azure Service Bus Data Owner
Everything seems to work fine and the app successfully processes messages from Service Bus using identity but looking at the FunctionsLogs for the app I see a lot of entries with "Unable to get table reference. Aborting write operation" and "Azure Storage connection string is empty or invalid. Unable to write diagnostic events." exceptions in logs.

This could be is due to the WebHost expecting only a connection string to write to table storage and not checking for identity-based connections. Worried this could happen for any app that has storage diagnostics settings on.
https://github.com/Azure/azure-functions-host/src/WebJobs.Script.WebHost/Diagnostics/DiagnosticEventTableStorageRepository.cs#L64