fix(authentication): stream on null account

packages/wyatt_authentication_bloc/lib/src/data/data_sources/remote/authentication_firebase_data_source_impl.dart

@@ -101,9 +101,12 @@ class AuthenticationFirebaseDataSourceImpl
   @override
   Stream<Account?> streamAccount() =>
       _firebaseAuth.userChanges().map<Account?>((user) {
+        if (user.isNull) {
+          return null;
+        }
         try {
           return AccountModelFirebase.fromFirebaseUser(user);
-        } on FirebaseAuthException {
+        } on Exception {
           return null;
         }
       });