By Anna Mehler Paperny, Ismail Shakil and Jarrett Renshaw OTTAWA/WASHINGTON (Reuters) -Protesters blocking border crossings between Canada and the United States risk hurting the auto industry, the White House warned on Wednesday as Ottawa urged an end to the 13-day demonstration against coronavirus mandates. The Ambassador Bridge, a key supply route for the U.S. auto industry in Detroit, has been shut for inbound Canada traffic since Monday night. Another border crossing in Alberta has been closed in both directions since late on Tuesday. Starting as a “Freedom Convoy” occupying downtown Ottaw…