[Bug Report] 2.15.9 版本时间组件控制台都报错

### Element UI version
2.15.9

### OS/Browsers version
window10/chrome 103.0.5060.134

### Vue version
2.6.11

### Reproduction Link
https://codepen.io/jinghh/pen/mdxBXME

### Steps to reproduce
使用2.15.9版本，使用时间组件控制台报错，使用2.15.8则正常

### What is Expected?
不报错

### What is actually happening?
[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"