Native auth: Email OTP MFA to Match EC Implementation, Fixes AB#3351233

[nilo-ms]

This PR updates the SDK to match the latest flow from EC.

In this new flow, the developer must always supply an auth Method to the /oauth2/v2.0/challenge endpoint which means once the .mfaRequired error is received from token endpoint, the /oauth2/v2.0/introspect endpoint needs to be called to retrieve the methods which are automatically returned to the external developer.

Furthermore, whenever calling the /token endpoint is called with an MFA Email OTP code, the grant type should be mfa_oob

Fixes AB#3351233

MSAL PR: AzureAD/microsoft-authentication-library-for-android#2380

[Copilot]

Pull Request Overview

This PR updates the Native Auth SDK to align with the latest EC implementation flow for Email OTP MFA. The key change involves removing the IntrospectRequired response handling and ensuring that MFA flows automatically call the introspect endpoint to retrieve authentication methods, returning them directly to the developer.

• Removes IntrospectRequired error response handling and related test infrastructure
• Updates MFA flow to automatically call introspect endpoint when MFA is required
• Adds MFA_OOB grant type support for Email OTP submissions

Reviewed Changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
MockApiResponseType.kt	Removes INTROSPECT_REQUIRED enum value
NativeAuthResponseHandlerTest.kt	Removes test for IntrospectRequired challenge response
NativeAuthRequestProviderTest.kt	Adds test assertions for MFA grant type handling
ApiErrorResponseUtil.kt	Removes isIntrospectRequired utility function
SignInChallengeApiResult.kt	Removes IntrospectRequired result class
SignInChallengeApiResponse.kt	Removes IntrospectRequired response handling logic
SignInTokenRequest.kt	Adds MFA grant type parameter and conditional logic
NativeAuthRequestProvider.kt	Updates OOB token request creation with MFA grant type
NativeAuthConstants.kt	Adds MFA_OOB grant type constant
SignInCommandResult.kt	Updates MFARequired result to include auth methods instead of error details
MFACommandResult.kt	Removes SelectionRequired result class
SignInSubmitCodeCommandParameters.java	Adds isMFAGrantType boolean field
MFASelectedDefaultChallengeCommandParameters.java	Removes entire file
MFAChallengeAuthMethodCommandParameters.java	Renames and updates class structure
GetAuthMethodsCommandParameters.java	Removes entire file
PublicApiId.java	Removes unused API ID constants
CommandUtilTest.kt	Updates tests for MFA grant type handling
NativeAuthControllerTest.kt	Major test refactoring for new MFA flow
SignInOAuthStrategyTest.kt	Updates tests and removes IntrospectRequired test
CommandUtil.java	Adds MFA grant type handling in utility methods
NativeAuthMsalController.kt	Major refactoring of MFA handling logic
MFAChallengeCommand.kt	Updates parameter type reference
GetAuthMethodsCommand.kt	Removes entire file

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