antd-vue在deep选择器+scoped下编译变量名会丢失属性

下方less编译后会丢失color属性只包含了font-size, 如果不使用变量的形式就正常

### theme
```
@import "ant-design-vue/lib/style/themes/default.less";
@primary-color: #ed0a5a;
```

### antd-vue-table
```
<style scoped lang="less">
:deep(.ant-table) th{
  font-size: 12px;
  color: @primary-color !important;
}
</style>
```