Simplify model cache setting

project/code/TMV/ModelLoader.cs

@@ -33,15 +33,7 @@ public class ModelLoader
 
         // We don't care if this is null actually, we'll still cache that it's null lol
         var model = LoadModel(_pathManager, ref campaignName, modelName);
-        var key = (campaignName, modelName);
-        if (_cache.ContainsKey(key))
-        {
-            _cache[key] = model;
-        }
-        else
-        {
-            _cache.TryAdd(key, model);
-        }
+        _cache[(campaignName, modelName)] = model;
         return model == null ? model : model.Duplicate() as MeshInstance3D;
     }