feat(auth)!: remove deprecated functions

[Lyokone]

This PR removes all deprecated methods from the firebase_auth package in preparation for a breaking change release.

Removed Methods

• ActionCodeSettings.dynamicLinkDomain - Firebase Dynamic Links is deprecated and will be shut down
• MicrosoftAuthProvider.credential() - Use signInWithProvider(MicrosoftAuthProvider) instead
• FirebaseAuth.instanceFor() persistence parameter - Use setPersistence() instead
• FirebaseAuth.fetchSignInMethodsForEmail() - Removed for security best practices
• User.updateEmail() - Use verifyBeforeUpdateEmail() instead

Migration Guide

ActionCodeSettings

// Before ActionCodeSettings( url: 'https://example.com', dynamicLinkDomain: 'example.page.link', ) // After ActionCodeSettings( url: 'https://example.com', linkDomain: 'your-custom-domain.com', // Use custom Firebase Hosting domain )

Microsoft Authentication

// Before final credential = MicrosoftAuthProvider.credential(accessToken); await FirebaseAuth.instance.signInWithCredential(credential); // After final provider = MicrosoftAuthProvider(); await FirebaseAuth.instance.signInWithProvider(provider);

FirebaseAuth Instance

// Before FirebaseAuth.instanceFor(app: app, persistence: Persistence.local); // After final auth = FirebaseAuth.instanceFor(app: app); auth.setPersistence(Persistence.local);

Email Updates

// Before await user.updateEmail('new@email.com'); // After await user.verifyBeforeUpdateEmail('new@email.com');

Email Sign-in Methods

The fetchSignInMethodsForEmail() method has been removed for security reasons. Consider implementing alternative authentication flows that don't require email enumeration.