iOS: TTS Does Not Follow Position When Swiping or Navigating During Playback

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When a book is playing with TTS, changing the reading position does not cause the TTS playback to follow the new position. TTS continues reading from the position it was previously playing instead of starting from the newly selected position.

Steps to Reproduce

1. Open a book.
2. Press Play to start TTS playback.
3. Leave TTS playing.
4. Swipe down on the Pause button, or use the navigation unit buttons to move to a different position.
5. Observe the TTS playback.