fix(nuxi): fix parsing bug for .npmrc files with comments

[odanado]

🔗 Linked issue

resolves https://github.com/nuxt/cli/issues/880

❓ Type of change

• [ ] 📖 Documentation (updates to the documentation or readme)
• [x] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [ ] 👌 Enhancement (improving an existing functionality)
• [ ] ✨ 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

I have fixed a bug where parsing the registry URL fails when .npmrc contains comments.