应用: 拼多多
任务: 打开拼多多，搜索“手机壳”，点击第四个商品，点击参与砍价按钮
操作步骤:
step_id: 0
action: CLICK
step_id: 1
action: CLICK
step_id: 2
action: TYPE
type_text: 手机壳
step_id: 3
action: CLICK
step_id: 4
action: CLICK
step_id: 5
action: CLICK
step_id: 6
action: CLICK
step_id: 7
action: CLICK