v216 typescript updates

- `AvatarGripPose.Driving` added
- `Player.enterFocusedInteractionMode()` now takes `FocusedInteractionOptions`
  - `disableFocusExitButton` to disallow player leaving focused interaction. Defaults to false
- explicit constant `PVAR_CHARACTER_LIMIT` of 10,000 (this was documented as 10KB before).