JILL SERJEANT  THE Kanye West sneakers that helped turn athletic shoes into coveted fashion items are going up for sale at Sotheby's, carrying an estimate of more than $1 million. The sneakers were the prototypes for the Yeezy line developed by West and Mark Smith for Nike, and revealed by the rapper during his performance at the 2008 Grammy Awards. Sotheby's said that the Nike Air Yeezy 1 Prototypes are being offered for private sale, starting on Monday. The auction house described them as among the most valuable sneakers ever brought to market. Sneakers have become collectors items in recent…