MIMOSA SPENCER IT was a "kid in a candy store" moment for Billie Essco when he found himself in a cavernous space beneath the Louvre Museum in January last year, backstage before a show for fashion designer Virgil Abloh's luxury streetwear label Off-White. Essco, a 31-year-old Black American artist, musician and clothing designer from Buffalo, New York had made a last-minute decision to join his friend, rapper Westside Gunn, on a trip to Paris with hopes of sneaking into a show during Fashion Week. He never would have dreamt of hanging out with Abloh, who besides being the founder of…