remove redundant ;

Author: NickKhalow

Runtime/Scripts/Rooms/Participants/Participant.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Collections.Concurrent;;
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using LiveKit.Internal;
 using LiveKit.Proto;