Without privacy settings, use of the camera crashes a unity app

`PopCameraDepthTest[1011:1145587] [access] This app has crashed because it attempted to access privacy-sensitive data without a usage description.  The app's Info.plist must contain an NSCameraUsageDescription key with a string value explaining to the user how the app uses this data.`

Should be able to detect this and not crash. (maybe not unity specific)