fix(dragdrop): Preserve DragDropExtension JS entrypoint

Author: jeromelaban

src/Uno.UI/LinkerDefinition.Wasm.xml

@@ -13,6 +13,9 @@
 	<type fullname="Windows.UI.Xaml.Input.FocusManager">
 	  <method name="ReceiveFocusNative" />
 	</type>
+	<type fullname="Windows.ApplicationModel.DataTransfer.DragDrop.Core.DragDropExtension">
+	  <method name="OnNativeDropEvent" />
+	</type>
 	<type fullname="Windows.UI.Xaml.Application">
 	  <method name="DispatchSuspending" />
       <method name="DispatchSystemThemeChange" />