Enable Semantic Voice Activity detection using the SDK

[utkarsh-jha]

I was in process of migrating my application RealtimeClient layer from Websocket to OpenAI .NET SDK,

When configuring the session turn detection, I found the method TurnDetectionOptions.CreateSemanticVoiceActivityTurnDetectionOptions to be internal and because of which I can't use the following configuration.

ConversationSessionOptions sessionOptions = new()
{
    Instructions = _sessionConfig.SessionParams.Instruction,
    Voice = "alloy",
    InputAudioFormat = "pcm16",
    OutputAudioFormat = "pcm16",
    InputTranscriptionOptions = new InputTranscriptionOptions
    {
        Model = "whisper-1"
    },
    Temperature = 0.6f,
    // library currently has internal implementaions of 
    //TurnDetectionOptions.CreateSemanticVoiceActivityTurnDetectionOptions(
    //    eagerness: EagernessLevel.Medium,
    //    createResponse: true,
    //    interruptResponse: true),
};