Disney’s new live-action “Mulan” is coming at a time when the entertainment world is still feeling tremors from the success of “Crazy Rich Asians” and “Parasite.” It was a very different landscape when the animated “Mulan” debuted in 1998: U.S. audiences were far less used to the presence of Asians onscreen, and many Asian American moviegoers felt less comfortable with depictions of themselves.