After the [bug report] select component turns on filtering, the input text cannot be filtered or triggered after the selected text of the input method is selected by numbers

### Element UI version
2.13.1

### OS/Browsers version
Chrome 81.0.4044.92

### Vue version
2.6.10

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

### Steps to reproduce
1、点击输入框，输入想要过滤的关键字；
2、用键盘的数字键选定输入法选框中的文字（不能使用空格选定文字）；
3、select并没有执行过滤方法。

### What is Expected?
通过数字键盘选定过滤的关键字后能正常过滤option，能正常触发filter-method。

### What is actually happening?
option并没有过滤，且不执行filter-method