[REQUIRED] Use case description

Add SUPPLEMENTAL-CODECS support in both DASH and HLS.
-- HLS Specification: https://developer.apple.com/documentation/http-live-streaming/hls-authoring-specification-for-apple-devices-appendixes#The-SUPPLEMENTAL-CODECS-attribute
-- MPEG-DASH Specification: Let me know whether you need a copy of the specification. (See also Dash-Industry-Forum/dash.js#4585)

Example test stream: https://ott.dolby.com/browser_test_kit/cbcs/p81/24/dash.mpd

Currently, AndroidX Media doesn't support this property. If there are multiple Dolby Vision tracks in one adaptive playback set, AndroidX Media will take them as HEVC streams when parsing .m3u8 or .mpd file.

Proposed solution

I have created a pull request for this feature: #1785 for your reference.