AR Foundationがxcode上でエラーが起きた。iPhoneの画面も黒いまま（カメラが起動しない）。
AR Foundation had an error on xcode and iPhone had black screen.
No active UnityEngine.XR.ARSubsystems.XRSessionSubsystem is available. Please ensure that a valid loader configuration exists in the XR project settings.
以下のチェックボックをOFFにして、再度ONにしたら治った！
I turned off the following checkbox, turned it back on, and it worked!
