Do not serialize Parameters property on AuthenticationProperties (#31414)

* Do not serialize Parameters

Explicitly prevent the Parameters dictionary from being included in the deserialized payload.
See https://github.com/dotnet/aspnetcore/pull/31330#discussion_r605078290.

* Ignore props backed by Items

Also ignore the properties backed by the Items dictionary to minimise the size of the serialized JSON payload.

* Add ignoreLineEndingDifferences

Stop tests from failing on non-Windows OSs due to different line endings.