Migrate All lab helper methods to Key Vault/Region test migration.

[RyAuld]

Migrate Test Infrastructure from msidlab.com API to Key Vault + IMDS V2 Improvements

Overview

This PR contains two major improvements:

1. Complete migration of MSAL test infrastructure from direct msidlab.com API calls to Azure Key Vault-based data retrieval for improved reliability and maintainability
2. Comprehensive IMDS V2 enhancements including improved source detection logic, retry policies, and probe mechanisms

Key Changes

🔑 Key Vault Migration (Test Infrastructure Modernization)

Migrated Methods:

• B2C Tests: GetB2CLocalAccountAsync() now uses Key Vault secrets (B2C-User-IDLab-JSON, B2C-App-IDLABSAPPB2C-JSON) instead of direct API calls
• Arlington Tests: GetArlingtonUserAsync() and GetArlingtonADFSUserAsync() migrated to use Arlington Key Vault (ARL-User-IDLab-JSON, ARL-App-IDLABSAPP-JSON)
• CIAM Tests: GetCIAMUserAsync() now retrieves data from Key Vault (MSAL-User-CIAM-JSON, MSAL-App-CIAM-JSON) in MSIDLABCIAM6 tenant
• Regional Tests: Updated to use MSAL-APP-AzureADMultipleOrgs configuration in ID4SLAB1 tenant with eastus2 region

Benefits:

• ✅ Eliminates direct dependency on msidlab.com API for better reliability
• ✅ Centralized secret management through Azure Key Vault
• ✅ Improved test stability and reduced flakiness
• ✅ Better separation of concerns between test data and test logic

Implementation Pattern:
All migrations follow the established MergeKVLabDataAsync() pattern:

// Before: Direct API call
return GetLabUserDataAsync(UserQuery.B2CLocalAccountUserQuery);

// After: Key Vault-based retrieval
return MergeKVLabDataAsync("B2C-User-IDLab-JSON", "MSIDLABB2C", "B2C-App-IDLABSAPPB2C-JSON");

🔄 IMDS V2 Source Detection & Retry Policy Improvements

Enhanced Managed Identity Source Detection:

• Improved IMDS Probe Logic: Refactored probe mechanism with better error handling and fallback behavior
• Enhanced Retry Policies: Improved ImdsProbeRetryPolicy (renamed from CsrMetadataProbeRetryPolicy) with better exponential backoff
• Robust Source Detection: Better differentiation between IMDSv1, IMDSv2, and unavailable sources
• Timeout Handling: Added proper cancellation token support for probe operations

Key Improvements:

• 🔧 Better Error Recovery: Enhanced fallback logic when IMDSv2 is unavailable
• 🔧 Improved Performance: More efficient source detection with proper timeout handling
• 🔧 Enhanced Testing: Comprehensive test coverage for probe scenarios and edge cases
• 🔧 Code Organization: Better separation of concerns between probe logic and token acquisition

🏗️ Regional Configuration Updates

Updated Regional Test Configuration:

• Client ID: Updated from legacy MSIDLAB4 to 54a2d933-8bf8-483b-a8f8-0a31924f3c1f (MSAL-APP-AzureADMultipleOrgs)
• Tenant ID: Migrated to ID4SLAB1 tenant (10c419d4-4a50-45b2-aa4e-919fb84df24f)
• Regional Endpoint: Changed from centralus.login.microsoft.com to eastus2.login.microsoft.com
• Key Vault Integration: Now uses MsalTeam Key Vault with MSAL-APP-AzureADMultipleOrgs secret

🧹 Code Cleanup & Maintenance

Removed Legacy Code:

• Cleaned up unused helper methods in LabUserHelper.cs
• Removed obsolete caching mechanisms for API-based calls
• Simplified test setup patterns across multiple test suites

Enhanced Test Reliability:

• Added proper mock handling for IMDS probe scenarios
• Improved test isolation and reduced inter-test dependencies
• Better error handling and timeout management in tests

Files Changed

Core Infrastructure

• tests/Microsoft.Identity.Test.LabInfrastructure/LabUserHelper.cs - Key Vault migration implementation
• tests/Microsoft.Identity.Test.Integration.netcore/Infrastructure/ConfidentialAppSettings.cs - Regional configuration updates
• tests/Microsoft.Identity.Test.Common/TestConstants.cs - Regional endpoint updates

IMDS V2 Enhancements

• src/client/Microsoft.Identity.Client/ManagedIdentity/V2/ImdsV2ManagedIdentitySource.cs - Enhanced probe logic
• src/client/Microsoft.Identity.Client/Http/Retry/ImdsProbeRetryPolicy.cs - Improved retry policies (renamed)
• src/client/Microsoft.Identity.Client/ManagedIdentity/ManagedIdentityClient.cs - Better source detection
• src/client/Microsoft.Identity.Client/ManagedIdentity/V2/ImdsVersion.cs - New enumeration for version handling

Test Updates

• tests/Microsoft.Identity.Test.Integration.netcore/HeadlessTests/* - Updated to use new Key Vault patterns
• tests/Microsoft.Identity.Test.Unit/ManagedIdentityTests/* - Enhanced IMDS V2 test coverage
• tests/Microsoft.Identity.Test.Common/Core/Mocks/MockHelpers.cs - Improved mock support

Testing

• ✅ All existing tests updated to work with Key Vault-based data retrieval
• ✅ Comprehensive IMDS V2 probe test coverage added
• ✅ Regional configuration tests verify new tenant setup
• ✅ Enhanced mock scenarios for better test isolation
• ✅ Improved error handling test cases

Migration Impact

No Breaking Changes:

• All public APIs remain unchanged
• Test behavior is preserved while improving reliability
• Existing test scenarios continue to work seamlessly

Improved Reliability:

• Reduced dependency on external API availability
• Better error handling and retry mechanisms
• More stable CI/CD pipeline execution

Related Work

This PR consolidates multiple infrastructure improvements:

• Initial Key Vault integration patterns
• ADFS configuration migrations
• Regional test modernization
• IMDS V2 feature enhancements
• Test reliability improvements

The migration establishes a robust foundation for future test infrastructure enhancements while maintaining backward compatibility and improving overall system reliability.