fix(youtube): respect active SABR tracks on cold start

[Priveetee]

Part of InfinityLoop1308/PipePipe#2575

Pairs with the client-side lockscreen/background fix: InfinityLoop1308/PipePipeClient#70

Summary

While testing the Android 17 lockscreen issue, I found one SABR-side problem in the background/audio-only path.

Follow-up SABR requests already respected the active track state, but the first media request still behaved like audio + video were selected. In background playback this can make the session start with the wrong shape.

This makes the cold-start request respect the active SABR track types too.

Changes

• Use the stream state's enabled track bitfield for the first media request.
• Only write preferred audio formats when audio is active.
• Only write preferred video formats when video is active.
• Treat incomplete media-only SABR responses as recoverable and retry/reload instead of killing the session immediately.

Validation

Tested with the paired client patch on Pixel 8 / Android 17:

• foreground playback
• background audio
• lockscreen play/pause
• lockscreen seek backward / forward
• queue transition after lockscreen seek

Build:

• ./gradlew :extractor:compileJava
• git diff --check