Revert "disable new transition while toPictureSync is fixed" (#109327)

packages/flutter/lib/src/material/page_transitions_theme.dart

@@ -602,7 +602,7 @@ class ZoomPageTransitionsBuilder extends PageTransitionsBuilder {
     return _ZoomPageTransition(
       animation: animation,
       secondaryAnimation: secondaryAnimation,
-      preferRasterization: false, // TODO(jonahwilliams): https://github.com/flutter/flutter/issues/108389
+      preferRasterization: route?.preferRasterization ?? true,
       child: child,
     );
   }

packages/flutter/test/material/page_test.dart

@@ -174,7 +174,7 @@ void main() {
       MaterialApp(
         onGenerateRoute: (RouteSettings settings) {
           return MaterialPageRoute<void>(
-            // Defaults to false for _ZoomPageTransition due to https://github.com/flutter/flutter/issues/108389
+            preferRasterization: false,
             builder: (BuildContext context) {
               if (settings.name == '/') {
                 return const Material(child: Text('Page 1'));