Fixed UI Toolkit world space panels with dynamically created colliders not working with poke interactors. This was done by adding support for dynamically adding and removing colliders on interactables after registration. `XRBaseInteractable` now provides `RegisterCollider`, `UnregisterCollider`, `RefreshColliders`, and a `collidersChanged` event (with `CollidersChangedEventArgs`) for managing colliders at runtime. For UI Toolkit world space panels, colliders created dynamically by `UIDocument` are automatically registered when the `XRUIToolkitManager` is present in the scene.