By Michael Rosenberg One had to be told she could do anything. The other was always told she couldn’t. Now with Las Vegas, they both have their first WNBA title. Kelsey Plum dribbled the shot clock dry, then drove to the hoop, the simplest basketball act fueled by the purest of basketball motives. Last summer, the Aces retired Becky Hammon’s No. 25, and Hammon said last week, “I worked with Plum on her finishing.” Hammon was a Spurs assistant then. She says coaching the Aces “didn’t even cross my mind.” She helped Plum because it’s what coaches do. Now Plum took rock to rim; finished; did a ha…