Conflict with cached routes

[alex-osborn]

The Nova Pages tool doesn't load correctly when routes are cached with php artisan route:cache.

Steps to reproduce:

1. Load Nova, navigate to Pages tool. The tool load correctly.
2. Run php artisan route:cache.
3. Reload the tool. The tool does not load correctly.
4. Clear cached routes with php artisan route:clear.
5. Reload the tool. The tool loads correctly again.

From my debugging, appears as if the original Nova routes are used when caching is enabled which is giving a dependency injection error.