fix reward calculations (#5418)

Project/Assets/ML-Agents/Examples/Soccer/Scripts/AgentSoccer.cs

 
     public override void Initialize()
     {
-        m_Existential = 1f / MaxStep;
+        SoccerEnvController envController = GetComponentInParent<SoccerEnvController>();
+        if (envController != null)
+        {
+            m_Existential = 1f / envController.MaxEnvironmentSteps;
+        }
+        else
+        {
+            m_Existential = 1f / MaxStep;
+        }
+
         m_BehaviorParameters = gameObject.GetComponent<BehaviorParameters>();
         if (m_BehaviorParameters.TeamId == (int)Team.Blue)
         {

Project/Assets/ML-Agents/Examples/Soccer/Scripts/SoccerEnvController.cs

     /// Max Academy steps before this platform resets
     /// </summary>
     /// <returns></returns>
-    [Header("Max Environment Steps")] public int MaxEnvironmentSteps = 25000;
+    [Tooltip("Max Environment Steps")] public int MaxEnvironmentSteps = 25000;
 
     /// <summary>
     /// The area bounds.