public static boolean isWithinMarshmallowAndR() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && Build.VERSION.SDK_INT <= Build.VERSION_CODES.R;
    }
Returns true if write external permission has been requested at least twice and
user denied it, and checked 'Don't ask again'.

@param activity the activity
@return true if permission has been denied and the popup will not come up any more, false otherwise
app/src/main/java/no/nordicsemi/android/nrfmesh/utils/Utils.java