[Bug Report] el-date-picker类型为week，参数设置pickerOption的firstDayOfWeek为1时，当前周只有第一天时，点击无反应。 el-date-picker type is week,pickerOption's firstDayOfWeek:1,when this week just have first day,can not click

### Element UI version
2.15.13

### OS/Browsers version
chrome

### Vue version
2.7.14

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

### Steps to reproduce
picker-options参数如下：
{
disabledDate(time) {
return time.getTime() > Date.now() - 8.64e7
},
firstDayOfWeek: 1
}

### What is Expected?
可以点击

### What is actually happening?
不可以点击