fix(externals): skip resolving virtual ids start with \0

[pi0]

🔗 Linked issue

analogjs/analog#969 (comment)

Reproduction: https://github.com/brandonroberts/analog-nitro-295

❓ 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 fixes an issue revealed by #2289.

After calling (rollup) this.resolve, the result might be a virtual import starting with \0 which we shouldn't attempt to resolve using build-in ESM resolution (mlly).

📝 Checklist

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