fix: allow adding custom Vary to static assets handler

[daniluk4000]

🔗 Linked issue

Closes #2834

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Allow to auto-extend Vary header if Accept-Encoding is passed from Nitro.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[autofix-troubleshooter]

Hi! I'm the autofix.ci troubleshooter bot.

It looks like you correctly set up a CI job that uses the autofix.ci GitHub Action, but the autofix.ci GitHub App has not been installed for this repository. This means that autofix.ci unfortunately does not have the permissions to fix this pull request. If you are the repository owner, please install the app and then restart the CI workflow! 😃

[daniluk4000]

I sadly do not know locally what Prettier wants from me

[pi0]

Thnx!