ActionMenu - Reposition setting should be separate between Desktop and VR

[NotAKidoS]

Currently repositioning the menu in desktop also applies that offset to VR

kinda annoying, setting should be separate or desktop only

[dakyneko]

It's non trivial: MetaPort.Instance.isUsingVr is null during OnApplicationStart where those melon prefs are created. Not sure how to go about that.