Updating “Dataset of transcriptomic changes that occur in human preadipocytes over a 3-day course of exposure to 3, 3′, 4, 4′, 5-Pentachlorobiphenyl (PCB126)” with additional data on exposure to 2, 2′, 5, 5′-tetrachlorobiphenyl (PCB52) or its 4-hydroxy metabolite (4-OH-PCB52)