Callback for when translation begins
NOTE: The reason we need to add this event in FrameInputHandler, instead of relying on the container frame's internal InteractableManipulation component is because the way this class keeps track of state means that we don't set the InteractableManipulation's canTranslate property until after the user has started translating, which has the effect of causing InteractableManipulation to NOT invoke the onTranslationStart event.
Readonlystate
Callback for when translation ends