fix: [package:firefuel] Update Example Location

[SupposedlySam]

Reason for Change

The pub expects the example to be located in ./example/lib/main.dart. Ours was located in a nested folder inside of example and needed to be moved.

Proposed Changes

Move the example out of the nested folder and to the top level example folder

Type of Change

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

Checklist

• [ ] Readme Updated
• [x] Example project updated
• [x] Tests added/updated
• [ ] Changelog updated
• [ ] Pubspec version updated