[Bug Report] When using clearFiler('xxx') in Multilevel header table, it will cause problem

### Element UI version
2.13.1

### OS/Browsers version
macOs 10.13.6/Chrome 80.0.3987.149

### Vue version
2.6.11

### Reproduction Link
https://codepen.io/zzn1314/pen/qBOXERN?editors=1111

### Steps to reproduce
First step, click date and then choose one options, then click name and choose one options. You will see the error message in the console.

### What is Expected?
when first click, "日期" in the header should become active, and after click "姓名" and choose one option, "日期" should become inactive, without blue color.

### What is actually happening?
show error message in the console and still active