分组类型的select的change事件通过selectedItems无法获得被选择项

版本6.10

点击按钮后click事件是否可以触发另一个select组件的change事件，能否执行类似下面的动作

{
"actionType": "emit",
"componentId": "myForm:city", // 正确组件标识
"eventName": "change",
"args": {"value": "shanghai"}
}

Start by reproducing the version 6.10 configuration with a grouped select, a button click, and the select's change event. Trace the select change handling and the actionType "emit" entry point; done means the selected item is available through selectedItems and the button can emit the requested change event with the supplied value.

Written by the indexing model from the issue text.