Increase dart migrate integration test timeout (#77192)

packages/flutter_tools/test/integration.shard/migrate_test.dart

@@ -13,6 +13,7 @@ import 'test_utils.dart';
 void main() {
   /// Verifies that `dart migrate` will run successfully on the default `flutter create`
   /// template.
+  group('dart migrate', () {
     testWithoutContext('dart migrate succeeds on flutter create template', () async {
       Directory tempDir;
       try {
@@ -35,7 +36,7 @@ void main() {
       } finally {
         tempDir?.deleteSync(recursive: true);
       }
-  }, timeout: const Timeout(Duration(minutes: 1)));
+    });
 
     /// Verifies that `dart migrate` will run successfully on the module template
     /// used by `flutter create --template=plugin`.
@@ -62,6 +63,7 @@ void main() {
         tempDir?.deleteSync(recursive: true);
       }
     });
+  }, timeout: const Timeout(Duration(seconds: 90)));
 }
 
 Future<Directory> _createProject(Directory tempDir, [List<String> extraAgs]) async {