fix(frontend): 画面を閉じる直前にAudioContextを閉じるように

[kakkokari-gtyih]

What

書いてあるとおり

Why

Chrome 系 on macOS で AudioContext 開きっぱなしの状態でタブ閉じると他のタブのオーディオが壊れる問題にぶち当たる（らしい）

Additional info (optional)

Checklist

• Read the contribution guide
• Test working in a local environment
• (If needed) Add story of storybook
• (If needed) Update CHANGELOG.md
• (If possible) Add tests

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 19.12%. Comparing base (4120c9a) to head (34fee68).

Files with missing lines	Patch %	Lines
packages/frontend/src/scripts/sound.ts	0.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #15080      +/-   ##
===========================================
- Coverage    19.30%   19.12%   -0.19%     
===========================================
  Files          728      728              
  Lines       103971   103975       +4     
  Branches       991      993       +2     
===========================================
- Hits         20073    19883     -190     
- Misses       83344    83536     +192     
- Partials       554      556       +2     

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[syuilo]

chromeのバグということを明記した方が良さそう