chore: Remove using

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: MartinZikmund

src/Uno.UI/UI/Xaml/Controls/ToolTip/ToolTipService.cs

@@ -5,7 +5,6 @@
 using Uno.Disposables;
 using Uno.UI;
 using Uno.UI.Xaml.Core;
-using Windows.Media.Protection.PlayReady;
 using Windows.System;
 using Windows.UI;