fix(backend): fix apResolver

[kakkokari-gtyih]

What

Why

Additional info (optional)

Checklist

• [x] 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[bot]]

このPRによるapi.jsonの差分 差分はありません。 Get diff files from Workflow Page

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 39.96%. Comparing base (3a6c2aa) to head (a9e0ef4). Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ckages/backend/src/server/api/endpoints/ap/show.ts	0.00%	3 Missing :warning:
...ges/backend/src/core/activitypub/ApInboxService.ts	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #15010 +/- ## ======================================== Coverage 39.96% 39.96% ======================================== Files 1563 1563 Lines 197735 197737 +2 Branches 3633 3631 -2 ======================================== + Hits 79025 79026 +1 - Misses 118106 118138 +32 + Partials 604 573 -31 ```

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[syuilo]

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