refactor(ngAnimate): remove unused function argument

Closes #9585

src/ngAnimate/animate.js

@@ -1753,7 +1753,7 @@ angular.module('ngAnimate', ['ng'])
         // This will automatically be called by $animate so
         // there is no need to attach this internally to the
         // timeout done method.
-        function onEnd(cancelled) {
+        function onEnd() {
           element.off(css3AnimationEvents, onAnimationProgress);
           element.removeClass(activeClassName);
           element.removeClass(pendingClassName);