This option is deprecated, it will disappear in the next major release
`v4.0.0` (see Deprecated
APIs).
Returns the first text track of the video's element, null if none. This is equivalent to:
const el = player.getVideoElement();
const textTrack = el.textTracks.length ? el.textTracks[0] : null;player.getNativeTextTrack()- return value
TextTrack|null