fix(reporting): corrected promise and fs handling in SerenityBDDReporter/FileSystem
fix(reporting): corrected promise and fs handling in SerenityBDDReporter/FileSystem

affects: da39a3ee5e6b4b0d3255bfef95601890afd80709@serenity-js/core

jan-molak/serenity-js,jan-molak/serenity-js,jan-molak/serenity-js,jan-molak/serenity-js