[Gallery] Exclude semantics for logo and change to hint for products on Shrine (#292)

* Exclude logo from semantics

* Use hint instead of onTapHint as it otherwise won't work with VoiceOver

gallery/gallery/lib/studies/shrine/login.dart

@@ -85,18 +85,17 @@ class _ShrineLogo extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Column(
+    return ExcludeSemantics(
+      child: Column(
         children: [
-        Image.asset(
+          Image.asset('packages/shrine_images/diamond.png'),
-          'packages/shrine_images/diamond.png',
-          excludeFromSemantics: true,
-        ),
           const SizedBox(height: 16),
           Text(
             'SHRINE',
             style: Theme.of(context).textTheme.headline,
           ),
         ],
+      ),
     );
   }
 }

gallery/gallery/lib/studies/shrine/supplemental/product_card.dart

@@ -77,7 +77,7 @@ Widget _buildProductCard({
   return ScopedModelDescendant<AppStateModel>(
     builder: (context, child, model) {
       return Semantics(
-        onTapHint:
+        hint:
             GalleryLocalizations.of(context).shrineScreenReaderProductAddToCart,
         child: GestureDetector(
           onTap: () {