glib.setupHook: run glibPreFixupPhase before gappsWrapperArgsHook

Since we split wrapGAppsHook and move its variable initialization to preFixupPhases in #81475, it was getting run before glibPreFixupPhase which sets GSETTINGS_SCHEMAS_PATH variable gappsWrapperArgsHook depends on. Let's introduce this ugly hack to ensure glibPreFixupPhase will run before gappsWrapperArgsHook.