Avoid recursive disconnection in the TextBox lifetime test

Remove test children through their owning collection instead of recursively disconnecting the TextBox template. Recursive disconnection causes a delayed native fail-fast in WinUI TextBoxView teardown, aborting later unrelated tests. Keep the weak-reference collection assertion intact.

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

Author: 2 people

components/Extensions/tests/Element/FrameworkElementExtensionsTests.RelativeAncestor.cs

@@ -44,8 +44,7 @@ public async Task FrameworkElementExtension_RelativeAncestor_FreeParentBaseline(
 
         Assert.IsNotNull(parent, "Couldn't find parent Grid");
 
-        // Remove all the children from the grid to simulate it unloading.
-        VisualTreeHelper.DisconnectChildrenRecursive(parent);
+        // Let templated controls tear down their internal visual trees through normal unloading.
         parent.Children.Clear();
         parent = null;