Avoid send null current chapter when not needed

[StaehliJ]

Pull request

Description

The goal of this PR is to avoid sending onChapterChanged(null) when seeking to a chapter start position and the previous chapter end position are the same.

Changes made

• Self-explanatory.

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	50.84%	🟢
Files changed	100%	🟢

Module	Coverage
:pillarbox-player	50.17%	🟢

Files

Module	File	Coverage
:pillarbox-player	TimeRangeTracker.kt	95.53%	🟢