fix(backend): fix type error(s) in security fixes

[kakkokari-gtyih]

What

Why

Additional info (optional)

CIが通るまで待つ

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

[github-actions]

このPRによるapi.jsonの差分
差分はありません。
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[codecov]

Codecov Report

Attention: Patch coverage is 43.75000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 39.86%. Comparing base (53e827b) to head (99884c2).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/backend/src/core/HttpRequestService.ts	16.66%	5 Missing ⚠️
...end/src/core/activitypub/models/ApPersonService.ts	66.66%	3 Missing ⚠️
...kages/backend/src/core/RemoteUserResolveService.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           develop   #15009       +/-   ##
============================================
+ Coverage    19.33%   39.86%   +20.53%     
============================================
  Files          728     1563      +835     
  Lines       103798   197735    +93937     
  Branches       991     3634     +2643     
============================================
+ Hits         20066    78836    +58770     
- Misses       83178   118324    +35146     
- Partials       554      575       +21     

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[syuilo]

🙏