✨ [Feature]: Grid 表格是否可以加选中合计

[mww56]

What problem does this feature solve

Grid 表格是否可以加选中合计；
解决用户选中当前数据可以得到汇总的结果
类似下面图的效果

What does the proposed API look like

暂时没有想到什么方法

What is your project name

#1485

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Title: ✨ [Feature]: Whether the Grid table can be added to the selected total