HarmonyOS 全屏模态转场（bindContentCover）不支持自定义上下切换转场效果时间

可以看看下面这个样例，看看里面transition: TransitionEffect.asymmetric设置

https://gitee.com/openharmony/docs/blob/master/zh-cn/application-dev/reference/apis-arkui/arkui-ts/ts-universal-attributes-modal-transition.md#%E7%A4%BA%E4%BE%8B5

需要加上

transition: TransitionEffect.asymmetric(
  TransitionEffect.OPACITY.animation({ duration: 300 }).combine(
    TransitionEffect.move(TransitionEdge.BOTTOM).animation({duration:600}))
  ,
  TransitionEffect.OPACITY.animation({ duration: 400 }).combine(
    TransitionEffect.move(TransitionEdge.BOTTOM).animation({duration:600}))
),