[Bug Report] el-table type=selection, Unknown custom element el-checkbox | 表格控件 type为selection el-checkbox报未注册错误

### Element UI version
2.15.8 2.15.7

### OS/Browsers version
100.0.4896.75

### Vue version
2.6.14

### Steps to reproduce
1、按需引用el-table组件(不全局注册el-checkbox)
2、将第一列设为type="selection"
3、直接观察到表格中的勾选列 不显示勾选框

### What is Expected?
正常显示el-checkbox

### What is actually happening?
el-checkbox没被el-table引用