Fix linting issue: use if-null operator for nullable bool

packages/flutter/test/widgets/routes_test.dart

diff --git a/packages/flutter/test/widgets/routes_test.dart b/packages/flutter/test/widgets/routes_test.dart
index 952f82f..966d717 100644
--- a/packages/flutter/test/widgets/routes_test.dart
+++ b/packages/flutter/test/widgets/routes_test.dart
@@ -2729,7 +2729,7 @@
     
     final Semantics modalScopeSemantics = semanticsWidgets.firstWhere(
       (Semantics widget) => 
-        widget.properties.scopesRoute == true &&
+        (widget.properties.scopesRoute ?? false) &&
         widget.properties.hitTestBehavior != null,
     );