Fix build error

2020-08-22 00:00:00 +08:00 · 2020-08-22 00:00:00 +08:00 · fa46a1246e
--- a/Microsoft.Toolkit.Forms.UI.Controls/InkToolbar/InkToolbarCustomPenButton.cs
+++ b/Microsoft.Toolkit.Forms.UI.Controls/InkToolbar/InkToolbarCustomPenButton.cs
@ -8,7 +8,6 @@ using System.ComponentModel;
 using System.Linq;
 using Microsoft.Toolkit.Forms.UI.XamlHost;
 using Microsoft.Toolkit.Win32.UI.Controls.Interop.WinRT;
-using Microsoft.Toolkit.Win32.UI.Interop;
 using Windows.UI.Xaml;
 using windows = Windows;