[修正] 事件监听可能发生的内存溢出

src/app/working-area/working-area.component.ts

@@ -579,6 +579,7 @@ export class WorkingAreaComponent extends EventEmitter implements OnInit, AfterV
    */
   public destroyBackgroundImage(): void {
     this.app.stage.removeChild(this.backgroundImage);
+    this.removeAllListeners('backgroundScale');
   }
   /**
    * 设置背景图缩放