Add sentry to app

Sentry helps us keep track of app performance by tracking exceptions raised, logs recorded etc.
https://docs.sentry.io/platforms/flutter/
https://pub.dev/packages/sentry_flutter

Start with the Sentry Flutter documentation and the sentry_flutter package linked in the issue to determine the integration points and configuration required. The work is done when the app reports the exceptions, logs, and performance information described in the issue.

Written by the indexing model from the issue text.