🐛 [firebase_auth] Add proper errors handling

[rodion-m]

At the moment error code stored as string and we even don't have exhaustive enum of possible errors.
It was not easy, but I found error codes list. Actually I found two:
https://cloud.google.com/identity-platform/docs/error-codes
https://firebase.google.com/docs/reference/js/firebase.auth.Auth#signinwithcredential
So, I suggest this approach to error handling:

extension FirebaseAuthExceptionX on FirebaseAuthException {
  T handleErrors<T>({
    required T Function() defaultFallback,
    T Function()? accountExistsWithDifferentCredential,
    T Function()? missingPhoneNumber,
    T Function()? invalidPhoneNumber,
    T Function()? missingVerificationCode,
    T Function()? invalidVerificationCode,
    T Function()? missingVerificationId,
    T Function()? invalidVerificationId,
    T Function()? codeExpired,
    T Function()? invalidCredential,
    T Function()? userDisabled,
    T Function()? userNotFound,
    T Function()? operationNotAllowed,
    T Function()? captchaCheckFailed,
    T Function()? quotaExceeded,
    T Function()? wrongPassword,
    T Function()? unknown,
  }) {
    switch (code) {
      case FireBaseAuthErrorCode.accountExistsWithDifferentCredential:
        return (accountExistsWithDifferentCredential ?? defaultFallback).call();
      case FireBaseAuthErrorCode.missingPhoneNumber:
        return (missingPhoneNumber ?? defaultFallback).call();
      case FireBaseAuthErrorCode.invalidPhoneNumber:
        return (invalidPhoneNumber ?? defaultFallback).call();
      case FireBaseAuthErrorCode.missingVerificationCode:
        return (missingVerificationCode ?? defaultFallback).call();
      case FireBaseAuthErrorCode.invalidVerificationCode:
        return (invalidVerificationCode ?? defaultFallback).call();
      case FireBaseAuthErrorCode.missingVerificationId:
        return (missingVerificationId ?? defaultFallback).call();
      case FireBaseAuthErrorCode.invalidVerificationId:
        return (invalidVerificationId ?? defaultFallback).call();
      case FireBaseAuthErrorCode.codeExpired:
        return (codeExpired ?? defaultFallback).call();
      case FireBaseAuthErrorCode.invalidCredential:
        return (invalidCredential ?? defaultFallback).call();
      case FireBaseAuthErrorCode.userDisabled:
        return (userDisabled ?? defaultFallback).call();
      case FireBaseAuthErrorCode.userNotFound:
        return (userNotFound ?? defaultFallback).call();
      case FireBaseAuthErrorCode.operationNotAllowed:
        return (operationNotAllowed ?? defaultFallback).call();
      case FireBaseAuthErrorCode.captchaCheckFailed:
        return (captchaCheckFailed ?? defaultFallback).call();
      case FireBaseAuthErrorCode.quotaExceeded:
        return (quotaExceeded ?? defaultFallback).call();
      case FireBaseAuthErrorCode.wrongPassword:
        return (wrongPassword ?? defaultFallback).call();
      case FireBaseAuthErrorCode.missingClientIdentifier:
        return (missingClientIdentifier ?? defaultFallback).call();
      default:
        return (unknown ?? defaultFallback).call();
    }
  }
}

FireBaseAuthErrorCode

class FireBaseAuthErrorCode {

/// Thrown if there already exists an account with the email address asserted by the credential.
/// See: https://firebase.flutter.dev/docs/auth/error-handling/#handling-account-exists-with-different-credential-errors
static const accountExistsWithDifferentCredential = 'account-exists-with-different-credential';

/// Thrown if the SMS quota for the Firebase project has been exceeded.
static const quotaExceeded = 'quota-exceeded';

/// Thrown if the credential is malformed or has expired.
static const invalidCredential = 'invalid-credential';

/// Thrown if the type of account corresponding to the credential is not enabled.
/// Enable the account type in the Firebase Console, under the Auth tab.
static const operationNotAllowed = 'operation-not-allowed';

/// Thrown if the reCAPTCHA response token was invalid, expired, or if this method was called from a non-whitelisted domain.
static const captchaCheckFailed = 'captcha-check-failed';

static const missingPhoneNumber = 'missing-phone-number';
static const invalidPhoneNumber = 'invalid-phone-number';
static const missingVerificationCode = 'missing-verification-code';
static const invalidVerificationCode = 'invalid-verification-code';
static const missingVerificationId = 'missing-verification-id';
static const invalidVerificationId = 'invalid-verification-id';
static const codeExpired = 'code-expired';
static const userDisabled = 'user-disabled';
static const userNotFound = 'user-not-found';
static const wrongPassword = 'wrong-password';

}

Now we can use it like this:

try {
  final result = await FirebaseAuth.instance.signInWithCredential(credential);
  logger.info('Auth succeeded: $result');
} on FirebaseAuthException catch (e) {
  e.handleErrors(
	accountExistsWithDifferentCredential: () {
	  // todo: handle
	},
	invalidVerificationCode: () {
	  showError("Code is incorrect :(");
	},
	codeExpired: () {
	  showError("Code is expired :(");
	},
	defaultFallback: () {
	  showError('Error: ${e.code}');
	},
  );
}

It should be a part of API.
@Salakar @russellwheatley @rrousselGit Please review it and I'll make a PR.

[Lyokone]

Hello,
Modifying the errors API is already discussed here: #3273
I'll close this one in favor of the other