Removed "using" deprecated UNET transports (#242)

Removed two "using" statements for the deprecated UNET, which were causing errors

Author: A7AATE

com.community.netcode.extensions/Runtime/NetworkDiscovery/ExampleNetworkDiscoveryHud.cs

@@ -1,7 +1,6 @@
 using System.Collections.Generic;
 using System.Net;
 using Unity.Netcode;
-using Unity.Netcode.Transports.UNET;
 using Unity.Netcode.Transports.UTP;
 using UnityEngine;
 using Object = UnityEngine.Object;

com.community.netcode.extensions/Runtime/NetworkManagerHud/NetworkManagerHud.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Runtime.CompilerServices;
 using Unity.Netcode;
-using Unity.Netcode.Transports.UNET;
 using Unity.Netcode.Transports.UTP;
 using UnityEngine;