Jessica Biel Mike Coppola/MG24/Getty Images for The Met Museum/Vogue To prep for her return to the Met Gala after 11 years, Jessica Biel bathed in 20 pounds of epsom salt. In honor of this year’s theme of “Sleeping Beauties: Reawakening Fashion” and the dress code of “The Garden of Time,” Biel, 42, stunned in a…