[Bug Report] When el-image in a dynamic element, the image will request twice

### Element UI version
2.15.14

### OS/Browsers version
chrome 131.0.6778.108

### Vue version
2.6.11

### Reproduction Link
```

Vue Element Image Example

new Vue({
el: '#app',
data: {
task: []
},
mounted() {
setTimeout(() => {
this.task.push(1);
}, 1000);
}
});

```

### Steps to reproduce
The same issue as https://github.com/ElemeFE/element/issues/19712, the difference is when the el-image is in a dynamic element, the image will load twice.

### What is Expected?
load once

### What is actually happening?
load twice