add constraintmanager via code when also adding objectmanipulator

Author: David Kline

Assets/MRTK/SDK/Editor/Migration/ObjectManipulatorMigrationHandler.cs

@@ -22,6 +22,7 @@ public bool CanMigrate(GameObject gameObject)
         public void Migrate(GameObject gameObject)
         {
             var manipHandler = gameObject.GetComponent<ManipulationHandler>();
+            gameObject.AddComponent<ConstraintManager>();
             var objManip = gameObject.AddComponent<ObjectManipulator>();
 
             objManip.enabled = manipHandler.enabled;