chore(auth): add email otp mfa enums and types

[khatruong2009]

Issue #, if available:

Description of changes:

• add enum types for email mfa code
• regenerate auth SDKs
• add signInSteps
• add SDK bridge and plugin implementations

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[Equartey]

refactor: This logic can be reordered and reduced to improve readability. Look at my refactor below. While it could be simplified more, I believe this captures the concept of merging logic and maintaining a linear flow. Also I recommend testing/verifying its functionality with unit tests.

/// Sets the MFA settings for the user.
Future<void> setMfaSettings({
  required String accessToken,
  MfaPreference? sms,
  MfaPreference? totp,
  MfaPreference? email,
}) async {
  final UserMfaPreference(
    enabled: currentEnabled,
    preferred: currentPreference,
  ) = await _getRawUserSettings(accessToken: accessToken);

  final newPreferredMethods = [
    if (sms == MfaPreference.preferred) MfaType.sms,
    if (totp == MfaPreference.preferred) MfaType.totp,
    if (email == MfaPreference.preferred) MfaType.email,
  ];

  if (newPreferredMethods.length > 1) {
    throw const InvalidParameterException(
      'Cannot assign multiple MFA methods as preferred',
    );
  }

  MfaType? preferred = newPreferredMethods.isNotEmpty 
      ? newPreferredMethods.first 
      : currentPreference;

  final isCurrentPreferenceDisabled = switch (currentPreference) {
    MfaType.sms => sms == MfaPreference.disabled || sms == MfaPreference.notPreferred,
    MfaType.totp => totp == MfaPreference.disabled || totp == MfaPreference.notPreferred,
    MfaType.email => email == MfaPreference.disabled || email == MfaPreference.notPreferred,
    _ => false,
  };
  preferred = isCurrentPreferenceDisabled ? null : preferred;

  const enabledValues = [
    MfaPreference.enabled,
    MfaPreference.notPreferred,
    MfaPreference.preferred,
  ];

  bool isMfaEnabled(MfaType mfaType, MfaPreference? preference) {
    if (preference == MfaPreference.disabled) return false;
    return currentEnabled.contains(mfaType) || enabledValues.contains(preference);
  }

  final smsMfaSettings = SmsMfaSettingsType(
    enabled: isMfaEnabled(MfaType.sms, sms),
    preferredMfa: preferred == MfaType.sms,
  );
  final softwareTokenSettings = SoftwareTokenMfaSettingsType(
    enabled: isMfaEnabled(MfaType.totp, totp),
    preferredMfa: preferred == MfaType.totp,
  );
  final emailMfaSettings = EmailMfaSettingsType(
    enabled: isMfaEnabled(MfaType.email, email),
    preferredMfa: preferred == MfaType.email,
  );

  await setUserMfaPreference(
    SetUserMfaPreferenceRequest(
      accessToken: accessToken,
      smsMfaSettings: smsMfaSettings,
      softwareTokenMfaSettings: softwareTokenSettings,
      emailMfaSettings: emailMfaSettings,
    ),
  ).result;
}

new changes

[NikaHsn]

Q: should this be 'EMAIL_MFA_CODE'?

[khatruong2009]

This is to match the Cognito team renaming it to EMAIL_OTP rather than MFA.

[NikaHsn]

Q: why do we need to add this?

[khatruong2009]

The file is generated but doesn't have the .g.dart at the end