chore: Adjust assertions

src/SamplesApp/SamplesApp.Shared/App.Assertions.cs

@@ -81,7 +81,15 @@ partial class App
 		var textBoxView = new TextBoxView(textBox);
 		ApiExtensibility.CreateInstance<IOverlayTextBoxViewExtension>(textBoxView, out var textBoxViewExtension);
 		Assert.IsNotNull(textBoxViewExtension);
-		Assert.IsTrue(textBoxViewExtension!.IsOverlayLayerInitialized(rootFrame.XamlRoot));
+
+		if (textBoxViewExtension is not null)
+		{
+			Assert.IsTrue(textBoxViewExtension.IsOverlayLayerInitialized(rootFrame.XamlRoot));
+		}
+		else
+		{
+			Console.WriteLine($"TextBoxView is not available for this platform");
+		}
 #endif
 	}