When East Palo Alto's Sports Authority went dark following the retailer's bankruptcy and subsequent liquidation, it threatened to punch a hole in the city's bottom line. But it didn't take long to backfill the 50,000-square-foot box. On Monday, Target Corp. announced it would take over the space, opening a new "flexible format" Target there next July."It is a good thing because we do want that building not to sit idle," Mayor Donna Rutherford said in a brief phone chat this morning. "If there’s a business that can come in and get going, we’re supportive of that."