chore: update player public interface for types visibility

[dzianis-dashkevich]

Description

seekable, seeking, ended, networkState, readyState are not visible for typescript.

Specific Changes proposed

Move getters declarations directly to the player class.

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Change has been verified in an actual browser (Chrome, Firefox, IE)
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

[codecov]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (6a5e1ee) 83.45% compared to head (a6ad5e2) 82.65%.

Files	Patch %	Lines
src/js/player.js	46.15%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8525      +/-   ##
==========================================
- Coverage   83.45%   82.65%   -0.80%     
==========================================
  Files         113      113              
  Lines        7596     7605       +9     
  Branches     1827     1828       +1     
==========================================
- Hits         6339     6286      -53     
- Misses       1257     1319      +62     

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