FakeRedactorProvider should support configurable redactors per data classification

[geeknoid]

Right now, the FakeRedactorProvider only returns a single redactor for all data classifications. It should be made more flexible and support returning different redactors for different data classifications in order to be suitably flexible for use in tests. We currently have a test which needs to mock IRedactorProvider to deal with this limitation.

[evgenyfedorov2]

@geeknoid - is this the test https://github.com/dotnet/extensions/blob/35592770387cc0994ebc9b86450b57493f216b6e/test/Libraries/Microsoft.AspNetCore.Diagnostics.Middleware.Tests/Logging/RequestHeadersEnricherTests.cs#L76C1-L93C105 you are referring to?

[geeknoid]

Yep, that's the one. There may be more...