When playing a chained animation, the `nextAnim` property could get set to `undefined` which would stop the next animation in the queue from being set. The check now handles all falsey cases. Fix #5852
When playing a chained animation, the `nextAnim` property could get set to `undefined` which would stop the next animation in the queue from being set. The check now handles all falsey cases. Fix #5852

photonstorm/phaser,photonstorm/phaser