Previously, `getTrackFormat()` in `MediaExtractorCompat` returned a `MediaFormat` without setting `MediaFormat.KEY_DURATION`. With this change:
- `MediaFormat.KEY_DURATION` is set based on the track's duration, if available.
- If the track duration is unset, the duration from the seek map is used as a fallback.
- When neither duration is set, `MediaFormat.KEY_DURATION` remains unset.
This ensures that `MediaFormat.KEY_DURATION` is populated when possible, enhancing duration information availability.
PiperOrigin-RevId: 691395114