feat(video_player_platform_interface): refactor audio track API to use track objects

[nateshmbhat]

feat(video_player_platform_interface): refactor audio track API to use track objects

Summary

Refactors the audio track identification and selection API to use separate groupIndex and trackIndex integers instead of encoded string IDs, and updates selectAudioTrack to accept a VideoAudioTrack object for improved type safety and developer experience.

Breaking Changes

Version: 7.0.0 (major version bump)

1. VideoAudioTrack Structure Change

Before:

class VideoAudioTrack {
  final String id;  // Encoded as "groupIndex_trackIndex"
  final String label;
  final String language;
  // ...
}

Motivation :
The previous string-based track ID system had several issues:

Lack of Type Safety: String encoding/decoding of track indices was error-prone
Poor Developer Experience: Required developers to manually construct or parse track IDs
Platform Inconsistency: Different platforms (ExoPlayer vs AVFoundation) handle track groups differently, but this was hidden in string encoding
Unintuitive API: Users had to remember the format and construction of track IDs

Interface Breakout PR From : #9925

Pre-Review Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] page, which explains my responsibilities.
• I read and followed the [relevant style guides] and ran [the auto-formatter].
• I signed the [CLA].
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I [linked to at least one issue that this PR fixes] in the description above.
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy], or I have commented below to indicate which [version change exemption] this PR falls under[^1].
• I updated CHANGELOG.md to add a description of the change, [following repository CHANGELOG style], or I have commented below to indicate which [CHANGELOG exemption] this PR falls under[^1].
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which [test exemption] this PR falls under[^1].
• All existing and new tests are passing.

[gemini-code-assist]

Code Review

This pull request refactors the audio track API for the video_player_platform_interface package. It introduces a VideoAudioTrack class that uses groupIndex and trackIndex integers for track identification, replacing the previous string-based ID. The selectAudioTrack method is updated to accept a VideoAudioTrack object, improving type safety. This is a breaking change, reflected by a major version bump to 7.0.0. The CHANGELOG.md and tests have been updated accordingly.

[gemini-code-assist]

The current changelog is a bit confusing as it introduces a feature in a 6.6.0 entry and then immediately describes a breaking refactor of it in the 7.0.0 entry. Assuming 6.6.0 was not released, it would be clearer to combine these into a single entry for 7.0.0 that describes the audio track selection feature as it is being introduced in its final form. This will provide better clarity for users reading the release notes.

Suggested change

	## 7.0.0
	* **BREAKING CHANGE**: Refactors audio track identification system:
	* `VideoAudioTrack.id` (String) replaced with separate `groupIndex` (int) and `trackIndex` (int) properties.
	* `selectAudioTrack(int playerId, String trackId)` changed to `selectAudioTrack(int playerId, VideoAudioTrack track)` - now accepts the full track object instead of separate parameters.
	* This change provides better type safety and a more intuitive API for audio track selection.
	## 6.6.0
	* Adds `VideoAudioTrack` class and `getAudioTracks()`, `selectAudioTrack()`, `isAudioTrackSupportAvailable()` methods for audio track management.
	## 7.0.0
	* **BREAKING CHANGE**: Adds support for audio track selection.
	* Adds the `VideoAudioTrack` class, `getAudioTracks()`, `selectAudioTrack()`, and `isAudioTrackSupportAvailable()` methods for audio track management.
	* `VideoAudioTrack` uses `groupIndex` and `trackIndex` integers for identification.
	* `selectAudioTrack` accepts a `VideoAudioTrack` object for improved type safety.