fix an error

com.unity.uiwidgets/Runtime/widgets/layout_builder.cs

 
 namespace Unity.UIWidgets.widgets {
     public delegate Widget LayoutWidgetBuilder(BuildContext context, BoxConstraints constraints);
-    public delegate Widget ConstraintBuilder(BuildContext context, Constraints constraints);
+        public delegate Widget ConstraintBuilder(BuildContext context, ConstraintType constraints);
 
         
         public ConstrainedLayoutBuilder(

com.unity.uiwidgets/Runtime/widgets/orientation_builder.cs

 
         public readonly OrientationWidgetBuilder builder;
 
-        Widget _buildWithConstraints(BuildContext context, Constraints constraints) {
+        Widget _buildWithConstraints(BuildContext context, BoxConstraints constraints) {
-                ((BoxConstraints)constraints).maxWidth > ((BoxConstraints)constraints).maxHeight ? Orientation.landscape : Orientation.portrait;
+                constraints.maxWidth > constraints.maxHeight ? Orientation.landscape : Orientation.portrait;
             return builder(context, orientation);
         }