Packed.cs assumes x5c subject contains O, OU, C and CN

[Molyna]

The code in the IsValidPackedAttnCertSubject of the Packed.cs uses the Item[TKey] method from Dictionary on the keys O, OU, C and CN. If the x5c doesn't contain one of these keys it will result in an KeyNotFoundException. The KeyNotFoundException is then not caught resulting in the Verify method not throwing the more appropriate Fido2VerificationException

[Molyna]

Fixed with #344 but there is no tag in #344 to close this so manually closing it.