fix: Refactor error logic to remove PrefixedFirebaseError as a intermediate class

[jonathanedey]

This PR:

• Removes the internal PrefixedFirebaseError to directly extend service error classes from the exposed FirebaseError
• Moves hasCode() helper function to FirebaseError and encapsulate prefix logic in the service error classes
• Replaces instances of FirebaseError being used with a manual service error prefix.

This PR also creates specific error classes for Database, Firestore, Storage, and Machine Learning, replacing legacy instances where generic FirebaseError objects were thrown with hardcoded string prefixes.

[gemini-code-assist]

Code Review

This pull request refactors the error handling system by removing the PrefixedFirebaseError class and integrating its functionality directly into the base FirebaseError class. It introduces a new hasCode method to FirebaseError to allow checking error codes without explicit knowledge of service prefixes. Additionally, it defines new error code constants and types for the Database, Firestore, and Storage services. Feedback was provided regarding the hasCode implementation, noting that it should check against the full error code before attempting a prefixed match to ensure consistent behavior and support polymorphism.