Requirements for OTPCredentialRequestOptions.transport are incompatible with WebIDL

[mkruisselbrink]

In https://wicg.github.io/WebOTP/#OTPCredentialRequestOptions is written "This OPTIONAL member contains a hint as to how the server might receive the OTP. The values SHOULD be members of OTPCredentialTransportType but client platforms MUST ignore unknown values.".

However WebIDL requires that converting a string to an enum throws a TypeError (https://heycam.github.io/webidl/#es-enumeration) if the string is not a valid enum member. If you do want the behavior you're describing, you should probably define transport as a sequence<DOMString> instead?

[rmondello]

Issue seems very similar to #31.

[mkruisselbrink]

Ah, yes. Definitely a duplicate of that.