After Button.Group is abandoned and replaced by Space, there are rounded corners between buttons

[moreant]

• [x] I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

使得 Space 能真正替代 Button.Group

What does the proposed API look like?

期望得 Space :size="0" 时 中的按钮能默认去掉圆角，并 Space 提供 API 能关闭这个特性（类似按钮之间默认有空格）

https://codesandbox.io/s/button-group-fei-qi-hou-shi-yong-space-de-ti-dai-xiao-guo-yu-button-group-bu-yi-zhi-ant-design-vue-3-2-13-forked-pry1tz