Increase NAT discovery timeout to 5000ms (Ryubing#589)

1000ms was too fast on some slower networks. It would lead to an early
cancellation before device could be found.

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/P2pProxyServer.cs

@@ -113,7 +113,7 @@ public void Configure(ProxyConfig config)
         public async Task<ushort> NatPunch()
         {
             NatDiscoverer discoverer = new();
-            CancellationTokenSource cts = new(1000);
+            CancellationTokenSource cts = new(5000);
 
             NatDevice device;