IOS Client fail to connect to an MsQuic server with client certificate validation enabled

[guhetier]

IOS Client fail to connect to an MsQuic server with client certificate validation enabled.

• The server is configured to require client certificate validation
• The server is configured to defer the validation to the app
  • the expected behavior is that the application can decide to allow the connection even if the client doesn't provide a certificate

IOS client don't provide a client certificate. However, the connection is rejected with a TLS internal error instead of notifying the application.

The issue seems to be than in some circumstances, SChannel returns an internal error instead of "not found" when a certificate context is not present.

[guhetier]

Candidate fix merged, validating on a signed binary.