GameStop’s shares were down more than 15% in pre-market trading after the company reported a wider-than-expected sales drop — just hours before a highly anticipated YouTube livestream from star retail investor “Roaring Kitty” was expected to send the stock surging. The video-game retailer said Friday its net sales tumbled to $881.8 million in the quarter ended May 4, compared with$1.24 billion a year earlier. That was worse than Wall Street expected, with two analysts having predicted sales of $900 million ...