fix: remove deletion of prerenderedAt key

[Barbapapazes]

🔗 Linked issue

fix nuxt/nuxt#22948
fix #2279
fix nuxt/nuxt#22841

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 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)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

I don't know if this breaks anything because it was made as a hot fix for nuxt/nuxt#14927

📝 Checklist

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

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[Barbapapazes]

Hello @atinux, @pi0 and @farnabaz,

I'm tagging you cause you worked on this PR #1526 and I think that you know more than me if this bug is still here or if we can safely remove this fix (which cause some important issue)