When Lisa Walker heard about Sunday’s ugly Christmas sweater competition for dogs, she knew instantly which one of her Havanese Charlie’s many selections he would be wearing — the one her mother-in-law sent her from Chattanooga, Tenn. So there was Charlie at the Bark at Spark Howl-I-Day Party in San Francisco, looking like a winner in a royal blue sweater with white snowflakes accented by silver pom-poms and a ninja Santa drop-kicking a candy…