fix(backend): happy-domを使用後にcloseするように

[kakkokari-gtyih]

What

https://activitypub.software/TransFem-org/Sharkey/-/merge_requests/634

Why

メモリーリークを軽減できるかもしれない

Additional info (optional)

Checklist

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

[github-actions[bot]]

api.jsonの差分作成中にエラーが発生しました。詳細はWorkflowのログを確認してください。

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 39.71%. Comparing base (7f7445a) to head (67ef4ce). Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
...s/backend/src/core/activitypub/ApRequestService.ts	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14615 +/- ## =========================================== + Coverage 39.61% 39.71% +0.10% =========================================== Files 1541 1541 Lines 192371 192375 +4 Branches 3532 3528 -4 =========================================== + Hits 76211 76405 +194 + Misses 115564 115376 -188 + Partials 596 594 -2 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[syuilo]

doppy-ham

[syuilo]

🙏🏿