439 improve current media item tracker

[StaehliJ]

Pull request

Description

The goal of this PR is to improve custom media item tracking. It fixe an issue where MediaItemTracker doesn't start when a given MediaItem with mediaId and url is set.

Changes made

• MediaItemTracker start and stop accordingly when either input MediaItem contain mediaId and url.
• MediaItemTracker.update is called correctly when data has changed.
• Add or remove tracker data during playback doesn't start or stop tracker.
• MediaItemTrackerData is now immutable to follow MediaItem immutability.

Checklist

• Your branch has been rebased onto the main branch.
• APIs have been properly documented (if relevant).
• The documentation has been updated (if relevant).
• New unit tests have been written (if relevant).
• The demo has been updated (if relevant).
• All pull request status checks pass.

[github-actions]

Code Coverage

Overall Project	21.21% -1.92%	🟢
Files changed	21.38%	🟢

Module	Coverage
:pillarbox-player	26.24% -5.29%	🟢
:pillarbox-core-business	25.77% -1.07%	🟢

Files

Module	File	Coverage
:pillarbox-player	MediaItemTrackerData.kt	90% -10%	🟢
	MediaItem.kt	88.1%	🟢
	PillarboxPlayer.kt	11.39% -2.22%	🟢
	CurrentMediaItemTracker.kt	0% -58.65%	🟢
	PillarboxMediaSource.kt	0% -9.78%	🟢
:pillarbox-core-business	MediaCompositionMediaItemSource.kt	17.06% -8.94%	🟢

[MGaetan89]

All good 👍🏻
I just have a couple of clarification questions, and pushed some minor changes.