fix: Permissions for changelog preview workflow

[jamescrosswell]

Not sure how this worked before merging, but it appears to require a permission that it's missing.

See https://github.com/getsentry/sentry-dotnet/actions/runs/21570267671:

The workflow is not valid. .github/workflows/changelog-preview.yml (Line: 16, Col: 3): Error calling workflow 'getsentry/craft/.github/workflows/changelog-preview.yml@v2'. The workflow is requesting 'statuses: write', but is only allowed 'statuses: none'.

#skip-changelog

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

---

This PR will not appear in the changelog.

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_{🤖 This preview updates automatically when you update the PR.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.85%. Comparing base (5dde625) to head (f521094).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4884      +/-   ##
==========================================
- Coverage   73.86%   73.85%   -0.01%     
==========================================
  Files         483      483              
  Lines       17577    17577              
  Branches     3464     3464              
==========================================
- Hits        12983    12982       -1     
  Misses       3741     3741              
- Partials      853      854       +1     

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