Removed one way to source binding from BindingTest.

As it was clearing the binding value when the program was run. Not sure
why it didn't do that before as it is correct behavior.

samples/BindingTest/MainWindow.paml

@@ -10,7 +10,6 @@
             <TextBox Watermark="Two Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue}" Name="first"/>
             <TextBox Watermark="One Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneWay}"/>
             <TextBox Watermark="One Time" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneTime}"/>
-            <!--<TextBox Watermark="One Way To Source" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneWayToSource}"/>-->
           </StackPanel>
           <StackPanel Margin="18" Gap="4" Width="200">
             <TextBlock FontSize="16" Text="Collection Bindings"/>