PointerEnterEvent and PointerExitEvent can only be created from hover events #29696
Description
When testing mouse hover support in a custom embedder, @ds84182 noticed crashes in MouseTracker due to an implicit downcast from PointerEvent to PointerHoverEvent. The _lastMouseEvent map can contain PointerMoveEvents and PointerDownEvents, in addition to PointerHoverEvents, so it should allow a PointerEvent, not just PointerHoverEvents.