应用: 腾讯会议
任务: 启动腾讯会议，点击‘加入会议’，输入会议号加入‘999-888-777’
操作步骤:
step_id: 0
action: CLICK
step_id: 1
action: CLICK
step_id: 2
action: TYPE
type_text: 999-888-777
step_id: 3
action: CLICK
step_id: 4
action: STOP