UI - Update Avalonia to preview7

UI - Update FluentAvalonia to preview7

src/Artemis.UI.Shared/Utilities.cs

@@ -4,6 +4,7 @@ using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using Avalonia.Controls;
 using Avalonia.Input;
+using Avalonia.Input.Platform;
 using IContainer = DryIoc.IContainer;
 
 namespace Artemis.UI.Shared;
@@ -26,6 +27,11 @@ public static class UI
     /// </summary>
     public static IContainer Locator { get; set; } = null!;
 
+    /// <summary>
+    ///     Gets the clipboard.
+    /// </summary>
+    public static IClipboard Clipboard { get; set; } = null!;
+
     /// <summary>
     ///     Gets a boolean indicating whether hotkeys are to be disabled.
     /// </summary>