Remove unused import to fix cocoon (#1898)

diff --git a/dashboard/test/utils/golden.dart b/dashboard/test/utils/golden.dart
index e2523d9..8b967d8 100644
--- a/dashboard/test/utils/golden.dart
+++ b/dashboard/test/utils/golden.dart
@@ -4,7 +4,6 @@
 
 import 'dart:developer';
 import 'dart:io';
-import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter_test/flutter_test.dart';