Add stacktraces to the sync status

[js2702]

When reporting unknown errors from the sync status stream we noticed that stacktraces are not included. This would be useful for better integration and debugging with tools such as Crashlytics/Sentry.

For instance we just received an event with the exception "ClosedException" without additional information.

[michaelbarnes]

Hey @js2702 thanks for the input. I'll pass it along to the team for further investigation.

[stevensJourney]

I've added this request to our internal queue of improvements.