chore(vercel): make experimental supportsResponseStreaming opt-in

[pi0]

🔗 Linked issue

#1505, #1514

❓ 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

This PR makes the change in #1514 (unreleased) opt-in as per requested by the Vercel team that they might make some platform changes

the team have reasons for not enabling supportsResponseStreaming by default for now (ongoing infra work) but there’s no problem encouraging users to enable it themselves.

📝 Checklist

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

[nuxt-studio]

✅ Live Preview ready!

Name	Edit	Preview	Latest Commit
nitro	Edit on Studio ↗︎	View Live Preview	97f0841

[pi0]

Seems was my misunderstanding! "you’re welcome to enable it by default, we just can’t on our end for the time being!"