Send bloc errors to sentry

lib/app_bloc_observer.dart

 import 'package:bloc/bloc.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
 
 import 'ui/logger.dart';
 
@@ -25,6 +26,7 @@ class AppBlocObserver extends BlocObserver {
   @override
   void onError(BlocBase<dynamic> bloc, Object error, StackTrace stackTrace) {
     super.onError(bloc, error, stackTrace);
+    Sentry.captureException(error, stackTrace: stackTrace);
     logger('onError -- $error');
     logger(stackTrace);
   }