table2下列选择器位置异常

#### 描述问题：

Table2属性下的类选择器样式异常

#### 截图或视频：


#### 如何复现（请务必完整填写下面内容）：
官网链接
https://aisuda.bce.baidu.com/amis/zh-CN/components/table2#%E8%A1%8C%E8%A7%92%E6%A0%87

Open the Table2 documentation at the linked official page and reproduce the class-selector positioning problem described in the issue, using the attached screenshot as reference. Trace the Table2 entry point and relevant selector styling, then verify that the selector appears in the intended position without regressing the documented row-marker behavior.

Written by the indexing model from the issue text.