refactor: Replace keycode dependency with event.key

[mister-ben]

Description

Removes the keycode dependency. That relies on now deprecated event properties. KeyboardEvent.key is now ubiquitous, so can be used directly instead.

Reduces min.js slightly, 646.9 kB => 645.22 kB

The uses of deprecated keyCode in utils/spatial-navigation-keycode.js ought to be reviewed too.

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: Patch coverage is 33.33333% with 24 lines in your changes are missing coverage. Please review.

Project coverage is 83.00%. Comparing base (978731e) to head (986a8bd).
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/js/control-bar/progress-control/seek-bar.js	0.00%	7 Missing ⚠️
src/js/menu/menu-button.js	0.00%	6 Missing ⚠️
src/js/slider/slider.js	0.00%	6 Missing ⚠️
src/js/control-bar/volume-panel.js	0.00%	2 Missing ⚠️
src/js/menu/menu.js	0.00%	2 Missing ⚠️
src/js/menu/menu-item.js	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8735      +/-   ##
==========================================
- Coverage   83.15%   83.00%   -0.15%     
==========================================
  Files         120      119       -1     
  Lines        7995     7991       -4     
  Branches     1924     1921       -3     
==========================================
- Hits         6648     6633      -15     
- Misses       1347     1358      +11     

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