- Updated `HeyGenVideoService` and `HeyGenTransport` to support both HeyGen APIs (Interactive Avatar and Live Avatar).
  Using them is as simple as specifying the `service_type` when creating the `HeyGenVideoService` and the `HeyGenTransport`:
  ```python
  heyGen = HeyGenVideoService(
      api_key=os.getenv("HEYGEN_LIVE_AVATAR_API_KEY"),
      service_type=ServiceType.LIVE_AVATAR,
      session=session,
  )
  ```