By Elizabeth Howcroft LONDON (Reuters) -Auction houses Christie’s, Sotheby’s and Bonhams have cancelled sales of Russian art in London in June, part of the art market’s response to Western sanctions on Russia as punishment for its invasion of Ukraine. The auction houses hold sales of Russian art in June and November in a period known as “Russian Art Week”, attracting wealthy Russian buyers. Sotheby’s said it had called off its sale of Russian art in London in June. “We are absolutely rigorous about following the present sanctions, and are monitoring closely for any updates to the lists,” it sa…