fix: Support json format in Firebase options for web for firebase CLI >=13.31.0

[yorifuji]

Description

Updated to support the new output format of apps:sdkconfig command introduced in Firebase CLI v13.31.0, which changed from JavaScript to JSON format for web apps.

• First pass at auto generating sdk configs firebase/firebase-tools#7833

Old format (before Firebase CLI v13.31.0):

firebase.initializeApp({
  "projectId": "my-project",
  "appId": "1:1234567890:web:abcdef1234567890",
  "apiKey": "api-key",
  "authDomain": "my-project.firebaseapp.com",
  "messagingSenderId": "1234567890",
  "measurementId": "G-ABCDEF1234"
});

New format (Firebase CLI v13.31.0 and later):

{
  "projectId": "my-project",
  "appId": "1:1234567890:web:abcdef1234567890",
  "apiKey": "api-key",
  "authDomain": "my-project.firebaseapp.com",
  "messagingSenderId": "1234567890",
  "measurementId": "G-ABCDEF1234"
}

Updated convertConfigToOptions to handle both formats and added unit tests.

Related issue

fixes #372

Type of Change

• ✨ feat -- New feature (non-breaking change which adds functionality)
• 🛠️ fix -- Bug fix (non-breaking change which fixes an issue)
• ❌ ! -- Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 refactor -- Code refactor
• ✅ ci -- Build configuration change
• 📝 docs -- Documentation
• 🗑️ chore -- Chore

[CLAassistant]

All committers have signed the CLA.

[russellwheatley]

@yorifuji - thank you for the effort. LGTM 🚀