loginWithApple function
Implementation
Future<User?> loginWithApple() async {
final appleProvider = AppleAuthProvider();
if (kIsWeb) {
UserCredential credential =
await FirebaseAuth.instance.signInWithPopup(appleProvider);
return credential.user;
} else {
UserCredential credential =
await FirebaseAuth.instance.signInWithProvider(appleProvider);
return credential.user;
}
}