[bug report] date picker type = "date" title can be clicked to select month and year type = "daterange" no, antd can

### Element UI version
2.15.7

### OS/Browsers version
goole

### Vue version
2.6.14

### Reproduction Link
https://codepen.io/lihuan-bot/pen/MWEwKQj

### Steps to reproduce
date-picker type = "date" 标题可以点击选择年月 type = "daterange" 不行

### What is Expected?
type = "daterange" 标题可以点击选择年月

### What is actually happening?
type = "daterange" 不行