Enable sign-out and tasks for all tenants

[mmacy]

This enables both sign-out and task list functionality when using a tenant in one's own B2C directory or the demo fabrikamb2c tenant.

The sample currently functions out of the box using the demo tenant, fabrikamb2c, but if one follows these B2C tutorials to configure it for their own B2C tenant, neither sign-out nor the task list work correctly:

• Tutorial: Enable authentication in a web application using Azure Active Directory B2C
• Tutorial: Grant access to an ASP.NET web API using Azure Active Directory B2C

There is also a follow-up update I'll be making to the API doc as it's missing a needed modification to the TaskService/Web.config (addresses the busted To-Do portion of MicrosoftDocs/azure-docs#38447).

Cc: @jennyf19 @yoelhor

[jennyf19]

@TiagoBrenck and @jmprieur I know you have plans for this sample. putting this PR on your radar. thx.

[jmprieur]

LGTM, @mmacy thanks!
do you have the rights to merge?

[mmacy]

@jmprier Excellent! And, no, I have no merge capability in this repo.

[jmprieur]

Thanks @mmacy . Merged!

[TiagoBrenck]

@mmacy if you navigate to Azure Portal > Azure AD B2C > User flows (policies) > Your sign up/in policy > Application claims, you will see the Object ID checkbox. By checking it would fix your logout issue.

I will evaluate if we need to revert the changes since we are using OID for the token cache as a standard in many samples.

[mmacy]

Thanks, @TiagoBrenck. I think the issue stems from MSAL remapping (?) the claim name from sub, which B2C always returns, to the NameIdentifier claim type value. Normally we rely on sub as oid isn't always returned (unless, as you say, you enable the object ID claim), so this change helps mitigate the requirement to have all our docs advise enabling the oid claim when sub as a default would normally work "out of the box."

[TiagoBrenck]

@mmacy you have a valid point. I think we use oid for token cache because since its value is the same on multiple applications in the same tenant, we would be able to share cache across apps.

I will open a thread with MSAL team about your point.