fix: dispose loadedAnimation native resource in Blazor Lottie sample

Skottie.Animation wraps a native resource (inherits SKObject/IDisposable).
The previous DisposeAsync cancelled and awaited the loop task and disposed
the CTS, but never disposed loadedAnimation, leaking native memory on every
page navigation.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mattleibow

samples/SkiaSharpDemo.Blazor/Pages/Lottie.razor

@@ -180,5 +180,6 @@
             catch (Exception) { }
         }
         animationCts?.Dispose();
+        loadedAnimation?.Dispose();
     }
 }