Fix 'Unknown or expired transaction ID.' in Mixer.InteractiveSample
Fix 'Unknown or expired transaction ID.' in Mixer.InteractiveSample

Previously, the InteractiveClient_OnGiveInput method was throwing a Mixer.Base.Util.ReplyPacketException, due to not checking for a null transactionID. This bug occurred when interacting with an interactive control without a spark cost.
SaviorXTanren/mixer-client-csharp