[Feature Request] When the disabled attribute of the "el-upload" component takes effect, there is no difference in the style. You want to add the no allowed style

### Existing Component
是

### Component Name
el-upload

### Description
When I use the "el-upload" component, I need to set the status of the echo image to unavailable, but set the disabled attribute, the cross style of the component has not changed, and the mouse cursor has no corresponding style.I hope it can be improved