Core/Errors: Stop using System.Diagnostics.Contracts, Its just closing the server without error or warning. We now log the error and then throw a exception

Source/Game/Handlers/CombatHandler.cs

@@ -21,7 +21,6 @@ using Game.Entities;
 using Game.Network;
 using Game.Network.Packets;
 using System;
-using System.Diagnostics.Contracts;
 
 namespace Game
 {
@@ -52,7 +51,7 @@ namespace Game
             if (vehicle)
             {
                 VehicleSeatRecord seat = vehicle.GetSeatForPassenger(GetPlayer());
-                Contract.Assert(seat != null);
+                Cypher.Assert(seat != null);
                 if (!seat.Flags.HasAnyFlag(VehicleSeatFlags.CanAttack))
                 {
                     SendAttackStop(enemy);