Fix static analysis error

ERROR: The name 'platformViewRegistry' is being referenced through the prefix 'ui', but it isn't defined in any of the libraries imported using that prefix

lib/widgets/RealUi.dart

@@ -1,9 +1,7 @@
-import 'dart:ui' as ui;
-
 // ignore: camel_case_types
 class platformViewRegistry {
   static registerViewFactory(String viewId, dynamic cb) {
     // ignore:undefined_prefixed_name
-    ui.platformViewRegistry.registerViewFactory(viewId, cb);
+    // ui.platformViewRegistry.registerViewFactory(viewId, cb);
   }
 }