HarmonyOS 鸿蒙Next PersistentStorage存储数据后，退出关闭应用，重新打开应用后AppStorage.get获取不到数据，得到的是undefined

1、PersistentStorage和UIContext相关联，需要在UIContext明确的时候才可以调用

2、在使用接口访问AppStorage中的属性之前需要调用PersistentStorage.persistProp。

可以参考如下代码做改造：

onWindowStageCreate(windowStage: window.WindowStage): void {
    // Main window is created, set main page for this ability
    hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageCreate');

    windowStage.loadContent('pages/testTarget', (err) => {
      if (err.code) {
        hilog.error(0x0000, 'testTag', 'Failed to load the content. Cause: %{public}s', JSON.stringify(err) ?? '');
        return;
      }
      hilog.info(0x0000, 'testTag', 'Succeeded in loading the content.');
    });

    let window = windowStage.getMainWindow()
    window.then(window => {
      let uicontext = window.getUIContext()
      uicontext.runScopedTask(() => {
        PersistentStorage.PersistProp('aProp2', 47);
        const path = AppStorage.get<number>('aProp2')
        if (path == 47) {
          console.log(`path is not OK`)
          AppStorage.setOrCreate("aProp2", 50)
        } else {
          console.log(`path is  OK`)
        }
      })
    })
}