fixed usim iteration offset

com.unity.perception/Runtime/Randomization/Scenarios/UnitySimulationScenario.cs

         public sealed override void DeserializeFromFile(string configFilePath)
         {
             base.DeserializeFromFile(configFilePath);
-            currentIteration = constants.instanceIndex * constants.instanceCount;
+            currentIteration = constants.instanceIndex;
         }
     }
 }