图片选择器实现使用PhotoViewPicker 看到之前已经选择过的图片

初始化时配置好preSelectUris来实现；

参考API：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-photoaccesshelper-V5

参考demo：

import { BusinessError } from '@ohos.base';
import photoAccessHelper from '@ohos.file.photoAccessHelper';
@Entry
@Component
struct Index {
  build() {
    Column() {
      Button('Sign in').width(150).margin({ top: 20 })
        .onClick(()=>{
          let PhotoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
          PhotoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE;
          PhotoSelectOptions.maxSelectNumber = 5;
          PhotoSelectOptions.preselectedUris = ['xxxxxx']
          let photoPicker = new photoAccessHelper.PhotoViewPicker();
          photoPicker.select(PhotoSelectOptions).then((PhotoSelectResult: photoAccessHelper.PhotoSelectResult) => {
            console.info('PhotoViewPicker.select successfully, PhotoSelectResult uri: ' + JSON.stringify(PhotoSelectResult));
          }).catch((err: BusinessError) => {
            console.error(`PhotoViewPicker.select failed with err: ${err.code}, ${err.message}`);
          });
        })
    }.padding(20)
  }
}