fix(backend): アンテナのソースになっているリストがnullな場合クエリータイムアウトが発生する問題を修正

[kakkokari-gtyih]

What

書いてあるとおり

Why

Additional info (optional)

フロントエンドは無いのね

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

差分はこちら

```diff ```

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.

Project coverage is 39.63%. Comparing base (0e4b6d1) to head (d49ac32). Report is 8 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/backend/src/core/AntennaService.ts	0.00%	8 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14568 +/- ## ============================================ + Coverage 19.54% 39.63% +20.08% ============================================ Files 713 1535 +822 Lines 100312 190849 +90537 Branches 997 3498 +2501 ============================================ + Hits 19610 75647 +56037 - Misses 80158 114641 +34483 - Partials 544 561 +17 ```

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[syuilo]

🙏🏿