[Bug Report] 引入日期组件会出现错误提示

### Element UI version
2.15.9

### OS/Browsers version
chrome 版本 103.0.5060.114（正式版本） （64 位）

### Vue version
2.7.8

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

### Steps to reproduce
引入el-date-picker就报错
[Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders. Instead, use a data or computed property based on the prop's value. Prop being mutated: "placement"

found in

---> at packages/date-picker/src/picker.vue

### What is Expected?
正常

### What is actually happening?
正常