fix(SDK): prevent SteamVR SDK reporting a button two press

Previously, the SteamVR SDK would report the Application Menu button
press as being ButtonOne and ButtonTwo. This is sematically incorrect
as the Vive controller does not have a button two and therefore
requesting if button two has been pressed should always return false.

Assets/VRTK/SDK/SteamVR/SDK_SteamVRController.cs

@@ -673,7 +673,7 @@ public override bool IsButtonOneTouchedUpOnIndex(uint index)
         /// <returns>Returns true if the button is continually being pressed.</returns>
         public override bool IsButtonTwoPressedOnIndex(uint index)
         {
-            return IsButtonPressed(index, ButtonPressTypes.Press, SteamVR_Controller.ButtonMask.ApplicationMenu);
+            return false;
         }
 
         /// <summary>
@@ -683,7 +683,7 @@ public override bool IsButtonTwoPressedOnIndex(uint index)
         /// <returns>Returns true if the button has just been pressed down.</returns>
         public override bool IsButtonTwoPressedDownOnIndex(uint index)
         {
-            return IsButtonPressed(index, ButtonPressTypes.PressDown, SteamVR_Controller.ButtonMask.ApplicationMenu);
+            return false;
         }
 
         /// <summary>
@@ -693,7 +693,7 @@ public override bool IsButtonTwoPressedDownOnIndex(uint index)
         /// <returns>Returns true if the button has just been released.</returns>
         public override bool IsButtonTwoPressedUpOnIndex(uint index)
         {
-            return IsButtonPressed(index, ButtonPressTypes.PressUp, SteamVR_Controller.ButtonMask.ApplicationMenu);
+            return false;
         }
 
         /// <summary>
@@ -713,7 +713,7 @@ public override bool IsButtonTwoTouchedOnIndex(uint index)
         /// <returns>Returns true if the button has just been touched down.</returns>
         public override bool IsButtonTwoTouchedDownOnIndex(uint index)
         {
-            return IsButtonPressed(index, ButtonPressTypes.TouchDown, SteamVR_Controller.ButtonMask.ApplicationMenu);
+            return false;
         }
 
         /// <summary>
@@ -723,7 +723,7 @@ public override bool IsButtonTwoTouchedDownOnIndex(uint index)
         /// <returns>Returns true if the button has just been released.</returns>
         public override bool IsButtonTwoTouchedUpOnIndex(uint index)
         {
-            return IsButtonPressed(index, ButtonPressTypes.TouchUp, SteamVR_Controller.ButtonMask.ApplicationMenu);
+            return false;
         }
 
         [RuntimeInitializeOnLoadMethod]