Error reporting

[HelloGrayson]

Sally's default server mode is optimized for Google App Engine Flexible - we should report errors in the format required for these errors to be surfaced in GCP tooling.

https://cloud.google.com/error-reporting/docs/setup/app-engine-flexible-environment

[erbesharat]

It's a really old issue, if there is still a need to work on this, I would be glad to take a look at it.