feat: Update DispatcherHelper to winui3/release/1.4.2

src/Uno.UI/Helpers/WinUI/DispatcherHelper.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+// MUX Reference DispatcherHelper.h, tag winui3/release/1.4.2
+
+using System;
+using Windows.UI.Xaml;
+
+namespace Uno.UI.Helpers.WinUI;
+
+internal class DispatcherHelper
+{
+	private Windows.System.DispatcherQueue dispatcherQueue;
+
+	public DispatcherHelper(DependencyObject dependencyObject = null)
+	{
+		dispatcherQueue = Windows.System.DispatcherQueue.GetForCurrentThread();
+	}
+
+	public void RunAsync(Action func, bool fallbackToThisThread = false)
+	{
+		var result = dispatcherQueue?.TryEnqueue(() => func()) ?? false;
+		if (!result)
+		{
+			if (fallbackToThisThread)
+			{
+				func();
+			}
+		}
+	}
+}