Update EntityTreeViewModel.cs to skip duplicate player identities (#624)

Skip adding to the players view model dictionary if it already contains that key, no idea if this will build

Author: TheCrunchy

Torch.Server/ViewModels/EntityTreeViewModel.cs

@@ -103,6 +103,8 @@ private void RegisterLiveNonEntities(ITorchSession session, TorchSessionState ne
                         if (identity.SteamId == 0) continue;
                         var player = MySession.Static.Players.TryGetPlayerIdentity(identity.SteamId);
                         if (player is null) continue;
+                        if (Players.ContainsKey(player.IdentityId)) continue;
+                        
                         Players.Add(new KeyValuePair<long, PlayerViewModel>(player.IdentityId, new PlayerViewModel(player, identity)));
                     }