HLS - When A/V are demuxed and video is disabled, video segments are still downloaded

# Question
I have tried to disable video renderer to cut down usage of network to play audio only mode.
However, while playing hls contents that audio and video are demuxed into separate streams, it keep loading video data, even though I disabled video renderer.
On the other hand, it works well without loading video data when playing DASH contents.

I am not sure whether this is a limitation of implementation or there is other way to resolve this.

```
2021-08-11 11:06:03.565 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=48.28, mediaPos=47.30, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/a2/fileSequence10.ac3]
2021-08-11 11:06:03.795 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=48.51, mediaPos=47.52, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/v9/fileSequence10.ts]
2021-08-11 11:06:09.584 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=54.30, mediaPos=53.32, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/a2/fileSequence11.ac3]
2021-08-11 11:06:09.815 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=54.53, mediaPos=53.55, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/v9/fileSequence11.ts]
2021-08-11 11:06:15.515 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=60.23, mediaPos=59.25, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/a2/fileSequence12.ac3]
2021-08-11 11:06:15.756 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=60.47, mediaPos=59.49, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/v9/fileSequence12.ts]
2021-08-11 11:06:21.608 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=66.33, mediaPos=65.35, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/a2/fileSequence13.ac3]
2021-08-11 11:06:21.877 8481-8481/com.google.android.exoplayer2.demo D/EventLogger: onLoadCompleted [eventTime=66.60, mediaPos=65.61, window=0, period=0, https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/v9/fileSequence13.ts]
```

# Environments
## Test Sample
Demo -> HLS -> `Apple master playlist advanced (ts)` and `Apple master playlist advanced (FMP4)`

## exoplayer version
2.14.2