fix(Pointer): ensure ToggleBeam() turns off bezier pointer

The `ToggleBeam` method was not turning off the bezier pointer as it
was only setting the bezier state to inactive but not actually changing
the visibility of the bezier pointer.

This fix ensures that the bezier pointer objects are turned off when
the beam is toggled off.

Assets/VRTK/Scripts/Pointers/VRTK_BezierPointer.cs

@@ -134,13 +134,25 @@ protected override void TogglePointer(bool state)
         {
             state = (pointerVisibility == pointerVisibilityStates.Always_On ? true : state);
             beamActive = state;
+            if (!beamActive)
+            {
+                ToggleBezierBeam(beamActive);
+            }
         }
 
         protected override void DisablePointerBeam(object sender, ControllerInteractionEventArgs e)
         {
             base.DisablePointerBeam(sender, e);
-            TogglePointerCursor(false);
-            curvedBeam.TogglePoints(false);
+            ToggleBezierBeam(false);
+        }
+
+        private void ToggleBezierBeam(bool state)
+        {
+            if (gameObject.activeInHierarchy)
+            {
+                TogglePointerCursor(state);
+                curvedBeam.TogglePoints(state);
+            }
         }
 
         private GameObject CreateCursor()

Assets/VRTK/Scripts/Pointers/VRTK_PlayAreaCursor.cs

@@ -116,7 +116,10 @@ public virtual void SetPlayAreaCursorTransform(Vector3 location)
         public virtual void ToggleState(bool state)
         {
             state = (!enabled ? false : state);
-            playAreaCursor.SetActive(state);
+            if (playAreaCursor)
+            {
+                playAreaCursor.SetActive(state);
+            }
         }
 
         protected virtual void Awake()