[Bug Report] click event of the indicator inside Carousel trigger abnormally

### Element UI version
2.13.0

### OS/Browsers version
win10 64bit / ie10, ie9

### Vue version
2.6.10

### Reproduction Link
https://codepen.io/-learner/pen/popKaxR

### Steps to reproduce
在input输入框中按下回车键

### What is Expected?
el-carousel应该正常轮播, 准备跳转到下一个el-carousel-item

### What is actually happening?
触发el-carousel的指示器第一个li标签的点击事件, el-carousel直接跳转到第一个el-carousel-item (在ie10和ie9中出现)