Change z index position so that navbar is above drawer
Change z index position so that navbar is above drawer


Former-commit-id: b5a04c8b0c0f7ae220b061763cb868a8133933a5
Former-commit-id: 684d315d6ce2a08dff7564df529fadcfd9bde97c
Former-commit-id: 2884eb4c96cf73bd0e1663a67c2078db24616587
ONSdigital/florence,ONSdigital/florence,ONSdigital/florence,ONSdigital/florence