Revert "Validating Visual's connection to visual tree (#8202)"

This reverts commit 647fadd7ff.

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/RadioButton.cs

@@ -161,7 +161,7 @@ namespace System.Windows.Controls
                         else
                         {
                             // Uncheck all checked RadioButtons different from the current one
-                            if (rb != this && (rb.IsChecked == true) && rootScope == KeyboardNavigation.GetVisualRoot(rb) && rootScope != null)
+                            if (rb != this && (rb.IsChecked == true) && rootScope == KeyboardNavigation.GetVisualRoot(rb))
                                 rb.UncheckRadioButton();
                             i++;
                         }