HarmonyOS 鸿蒙Next：request.agent.Task在app被杀掉后，根据id和token获取的Task的token会发生变化

建议使用以下demo：

import { BusinessError, request } from '@kit.BasicServicesKit';

@Entry
@Component
struct RequestTask {
  @State message: string = '';

  private task: request.agent.Task | undefined = undefined
  build() {
    Column() {
      Text('此demo为测试创建任务后，根据tid获取任务，没有直接使用存储tid的工具，所以您这边可以在创建任务后，在控制台把打印的tid记录下来，然后在输入框输入，用来查询任务')
      Button('创建任务').onClick(()=>{
        let config: request.agent.Config = {
          action: request.agent.Action.DOWNLOAD,
          url: '', // 需要手动将 url 替换为真实服务器的 HTTP 协议地址
          title: 'createTest',
          description: 'Sample code for create task',
          mode: request.agent.Mode.BACKGROUND,
          overwrite: true,
          saveas: "../../resources/rawfile/test.zip",
          gauge: false,
          precise: false,
          token: "123456789"
        };
        request.agent.create(getContext(), config, (err: BusinessError, task: request.agent.Task)=>{
          if (err) {
            console.error(`Failed to create a download task, Code: ${err.code}, message: ${err.message}`);
            return;
          }
          this.task = task
          console.info(`Succeeded in creating a download task. result: ${task.tid}`);
        });
      })
      Button('开始任务').onClick(()=>{
        console.log('开始任务')
        this.task?.start()
      })
      TextInput({
        placeholder:'请输入查询的taskId',
        text:this.message
      }).onChange((value: string) => {
        this.message = value
      })
      Button('获取任务').onClick(()=>{
        request.agent.getTask(getContext(), this.message,'123456789').then((task: request.agent.Task) => {
          console.info(`Succeeded in querying a upload task. result: ${JSON.stringify(task.config)}`);
        }).catch((err: BusinessError) => {
          console.error(`Failed to query a upload task, Code: ${err.code}, message: ${err.message}`);
        });
      })
    }
    .height('100%')
    .width('100%')
  }
}