bandaid for invalid master client id being sent by server

Runtime/VelNetManager.cs

@@ -472,8 +472,16 @@ namespace VelNet
 						case ChangeMasterMessage cm:
 						{
 							if (masterPlayer == null)
+							{
+								if (players.ContainsKey(cm.masterId))
 								{
 									masterPlayer = players[cm.masterId];
+								}
+								else
+								{
+									masterPlayer = players.Aggregate((p1, p2) => p1.Value.userid.CompareTo(p2.Value.userid) > 0 ? p1 : p2).Value;
+									Debug.LogError("Got an invalid master client id from the server. Using fallback.");
+								}
 
 								// no master player yet, add the scene objects