Declares a static method of a VisualElementComponentAttribute struct that runs when VisualElement.RemoveComponent removes the component from an element.
The method must be @@static void M(ref T self, VisualElement owner), and a
component may declare at most one. It runs before the component storage is freed and before
its [RegisterCallback] handlers are unregistered, so the method can still read its own
live data and clean up any owner state the component configured. It runs only on an explicit
RemoveComponent@@ call; it does not run when the element detaches from a panel or when
the element itself is torn down.