[bug report] the compound input box of select and input. After selecting a value, input is set to disabled

### Element UI version
2.13.2

### OS/Browsers version
win7/chrome 83

### Vue version
3.0.0-beta.15

### Reproduction Link
https://codepen.io/pen/

### Steps to reproduce
select选中餐厅名

### What is Expected?
input设置为disabled，左边select可以选择且cursor 仍然为 pointer

### What is actually happening?
左边select可以选择但是cursor 为 not-allowed