Add AC-4 Level-4 ISO base media file format support

[ybai001]

This pull request is same as https://github.com/androidx/media/pull/875. Since 875 is broken due to too many commit numbers, I re-created this new one.

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AC-4 Level-4 (Object Based Audio) is a Dolby official audio stream type for Atmos Music. This code update enables Android Media3 support local MP4 and MPEG-DASH AC-4 Level-4 playback.