Alysha Clark can measure her WNBA career in points and games and championships. But    there is nothing that marks the passage of time here quite like her 15-year-old chihuahua Sly.  She adopted him when she was desperate to land her first roster spot and he was just a puppy. Now, she’s wrapping up her 16th training camp and he’s “a little deaf and a little blind,” Clark says affectionately. As she grew more established in the WNBA, she felt secure enough to start bringing the dog to occasional team events like Media Day, and he’s unfazed by lights or music or noisy teammates. (Even if Clark now has to pick up Sly and carry him to reach the court for a photoshoot: He can’t navigate steps in mood lighting.) He’s made himself just as comfortable across the league as his mom has.…