Fix: Crossfade animation causes other animations to have hidden elements (#14832)

* Fix: Remove the property changes, let the animation take care of the opacity

* Fix: Remove disposables that are no longer required

---------

Co-authored-by: Matt Blacker <matt@aspireweb.com.au>

src/Avalonia.Base/Animation/CrossFade.cs

@@ -132,32 +132,23 @@ namespace Avalonia.Animation
             }
 
             var tasks = new List<Task>();
-            using (var disposables = new CompositeDisposable(1))
-            {
-                if (to != null)
-                {
-                    disposables.Add(to.SetValue(Visual.OpacityProperty, 0, Data.BindingPriority.Animation)!);
-                }
 
-                if (from != null)
+            if (from != null)
-                {
+            {
-                    from.Opacity = 0f;
+                tasks.Add(_fadeOutAnimation.RunAsync(from, null, cancellationToken));
-                    tasks.Add(_fadeOutAnimation.RunAsync(from, null, cancellationToken));
+            }
-                }
 
-                if (to != null)
+            if (to != null)
-                {
+            {
-                    to.Opacity = 1f;
+                to.IsVisible = true;
-                    to.IsVisible = true;
+                tasks.Add(_fadeInAnimation.RunAsync(to, null, cancellationToken));
-                    tasks.Add(_fadeInAnimation.RunAsync(to, null, cancellationToken));
+            }
-                }
 
-                await Task.WhenAll(tasks);
+            await Task.WhenAll(tasks);
 
-                if (from != null && !cancellationToken.IsCancellationRequested)
+            if (from != null && !cancellationToken.IsCancellationRequested)
-                {
+            {
-                    from.IsVisible = false;
+                from.IsVisible = false;
-                }
             }
         }