Merge pull request #9000 from JetBrains/fixes/8261-winuicomposition-loop

#8261 - terminating WinUIComposition loop on process exit to avoid cr…

src/Windows/Avalonia.Win32/WinRT/Composition/WinUICompositorConnection.cs

@@ -120,10 +120,14 @@ namespace Avalonia.Win32.WinRT.Composition
 
         private void RunLoop()
         {
+            var cts = new CancellationTokenSource();
+            AppDomain.CurrentDomain.ProcessExit += (sender, args) =>
+                cts.Cancel();
+                
             using (var act = _compositor5.RequestCommitAsync())
                 act.SetCompleted(new RunLoopHandler(this));
 
-            while (true)
+            while (!cts.IsCancellationRequested)
             {
                 UnmanagedMethods.GetMessage(out var msg, IntPtr.Zero, 0, 0);
                 lock (_pumpLock)