[#6589] Default to MSAL and eliminate ADAL without breaking changes

[sw-joelmut]

Fixes #6589

Description

This PR migrates ADAL related functionality to MSAL internally.

Note: The public JwtTokenProviderFactory class has been deprecated since its all related to ADAL functionality, said class is only being used for MSI classes, these classes will no longer use the deprecated provider and instead use the MSAL functionality.

Specific Changes

• AppCredentials.BuildAuthenticator has been deprecated and the BuildIAuthenticator method should be used instead.
• Added BuildIAuthenticator method to the CertificateAppCredentials class, providing the MSAL authenticator instance, also the internal class variables have been changed to minimize the ADAL implementation without generating breaking changes.
• Deprecated JwtTokenProviderFactory since it's no longer used in MSI related classes internally. Related classes will redirect any constructor using the provider to the one without it.
• Updated the ManagedIdentityAuthenticator class to use MSAL functionality instead of JwtTokenProviderFactory to acquire the token.
• Added BuildIAuthenticator method to the MicrosoftAppCredentials class, providing the MSAL authenticator instance.
• Removed the Microsoft.IdentityModel.Clients.ActiveDirectory (ADAL) package reference from Connector, since it's no longer used.
  • The Microsoft.Azure.Services.AppAuthentication package reference that uses ADAL underneath couldn't be removed, since it will generate breaking changes.
• Updated existing unit tests due to failures when providing and mocking the JwtTokenProviderFactory parameter class.
• Added new unit tests to validate the new implementation works as expected.

Testing

The following image shows a few bots working, the combination of skill bots and the FunctionalTests pipeline passing successfully.

[coveralls]

Pull Request Test Coverage Report for Build 351054

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 110 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-0.08%) to 79.026%

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Files with Coverage Reduction	New Missed Lines	%
/libraries/Microsoft.Bot.Connector.Streaming/Application/TimerAwaitable.cs	1	68.25%
/libraries/Microsoft.Bot.Streaming/Payloads/StreamManager.cs	1	90.0%
/libraries/Microsoft.Bot.Connector/Authentication/AppCredentials.cs	3	38.46%
/libraries/Microsoft.Bot.Connector/Authentication/ManagedIdentityAppCredentials.cs	4	63.64%
/libraries/Microsoft.Bot.Connector/Authentication/ManagedIdentityAuthenticator.cs	5	88.1%
/libraries/Microsoft.Bot.Connector/Authentication/MicrosoftAppCredentials.cs	23	40.91%
/libraries/Microsoft.Bot.Connector/Authentication/MsalAppCredentials.cs	25	0%
/libraries/Microsoft.Bot.Connector/Authentication/CertificateAppCredentials.cs	48	0%

Totals
Change from base Build 350786:	-0.08%
Covered Lines:	25851
Relevant Lines:	32712

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💛 - Coveralls

[BruceHaley]

✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.Integration.AspNet.Core.dll
✔️ No Binary Compatibility issues for Microsoft.Bot.Connector.dll