fix(menu): Fix #10005 lint error

Author: tinayuangao

src/lib/menu/menu-directive.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AnimationEvent} from '@angular/animations';
 import {FocusKeyManager} from '@angular/cdk/a11y';
 import {Direction} from '@angular/cdk/bidi';
 import {ESCAPE, LEFT_ARROW, RIGHT_ARROW} from '@angular/cdk/keycodes';