fix(backend): `Retry-After`ヘッダーが実際には送信されなかった問題を修正

[kakkokari-gtyih]

What

かいてあるとおり

Why

https://activitypub.software/TransFem-org/Sharkey/-/commit/8a982c61c01909e7540ff1be9f019df07c3f0624

Additional info (optional)

原因調査後 KisaragiEffective さんに確認していただくためDraft done

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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.

Project coverage is 39.70%. Comparing base (a18a6ac) to head (991b486). Report is 5 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/backend/src/server/api/ApiCallService.ts	0.00%	9 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14597 +/- ## =========================================== - Coverage 41.47% 39.70% -1.77% =========================================== Files 1545 1541 -4 Lines 197945 192208 -5737 Branches 3568 2562 -1006 =========================================== - Hits 82104 76324 -5780 - Misses 115247 115320 +73 + Partials 594 564 -30 ```

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

[github-actions[bot]]

このPRによるapi.jsonの差分

差分はこちら

```diff ```

Get diff files from Workflow Page

[kakkokari-gtyih]

a rate-limit-exceeded error has kind:'client', so the branch that adds the Retry-After would never get taken

これっぽいかも（retry-afterを送信する条件の前にkind:clientの条件に入ってヘッダが送信されない）

[KisaragiEffective]

自明なのでマージして良い？

[syuilo]

🙏🏿