Update 3p-e2e pipelines and native auth e2e tests

[yongdiw]

This pull request introduces new infrastructure and utilities to support end-to-end (E2E) testing for the NativeAuthSample in the MSAL browser samples. The most significant changes include the addition of configuration files and utility modules for handling test configuration, email-based OTP flows, and proxy management. It also updates the pipeline configuration to include the new sample and fixes a path in the Jest configuration.

[Copilot]

Pull request overview

This PR introduces comprehensive end-to-end testing infrastructure for the NativeAuthSample, enabling automated testing of native authentication flows including sign-up, sign-in, sign-out, and password reset scenarios. The implementation adds test utilities for email-based OTP verification, CORS proxy management, and centralized configuration handling.

Key changes:

• Adds 4 comprehensive test specification files covering positive and negative authentication flows
• Implements reusable utility modules for email provider integration, proxy management, and configuration parsing
• Fixes Jest configuration path and adds NativeAuthSample to the 3p-e2e pipeline

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 22 comments.

Show a summary per file

File	Description
samples/msal-browser-samples/NativeAuthSample/test/signup.spec.ts	Comprehensive sign-up flow tests with email+password and email+OTP scenarios including positive and negative test cases
samples/msal-browser-samples/NativeAuthSample/test/signin.spec.ts	Sign-in flow tests covering email+password and email+OTP authentication methods with error handling scenarios
samples/msal-browser-samples/NativeAuthSample/test/signout.spec.ts	Sign-out flow test validating session termination after successful authentication
samples/msal-browser-samples/NativeAuthSample/test/resetpassword.spec.ts	Password reset flow tests with positive and negative scenarios including OTP verification
samples/msal-browser-samples/NativeAuthSample/test/configUtils.ts	Centralized configuration management utility for test data, tenant info, and native auth settings
samples/msal-browser-samples/NativeAuthSample/test/emailProviderUtils.ts	Mail.tm API integration for automated email inbox creation and OTP code extraction
samples/msal-browser-samples/NativeAuthSample/test/proxyUtils.ts	CORS proxy server management utilities for test environment setup
samples/msal-browser-samples/NativeAuthSample/nativeAuthConfig.json	Native authentication configuration including client IDs, tenant details, and test credentials
samples/msal-browser-samples/NativeAuthSample/jest.config.cjs	Fixed Jest preset path from incorrect deep nesting to correct relative path
.pipelines/3p-e2e.yml	Added NativeAuthSample to the list of samples to test in the 3p-e2e pipeline