RIYADH — Ravers sporting face paint and flashing LED sunglasses jump in time to the thudding beats of Dish Dash, a DJ act whose rise mirrors that of the Saudi music scene.The confetti-strewn dance hall in Riyadh is packed with young men and women, most in streetwear hoodies and jeans, a few in traditional white robes and abayas.The setting bears scant resemblance to the venues