Fix build

Author: hez2010

src/Files.App/Views/Layouts/BaseLayoutPage.cs

@@ -15,6 +15,7 @@
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices.ComTypes;
+using Vanara.Extensions;
 using Vanara.PInvoke;
 using Windows.ApplicationModel.DataTransfer;
 using Windows.ApplicationModel.DataTransfer.DragDrop;