Multiple ReactSketchCanvas in one page causes issues due to id="background"
I wrapped `ReactSketchCanvas` to form a new component and used it multiple times in one page. I passed different imageSrc props and assigns it to `backgroundImage={props?.imageSrc}`.

v5.3.3 - works

v6.0.3 - doesn't work.

```
//DrawingComponent.js
function DrawingComponent(props) {
     ... 

     return (
                  <ReactSketchCanvas
                        ref={drawing}
                        style={styles}
                        width={'auto'}
                        height={512}
                        strokeWidth={1}
                        strokeColor={state.color}
                        backgroundImage={props?.imageSrc}
                    />
     )
}

//Usage
//Home.js

<DrawingComponent
    imageSrc={'image_path_1'}
    ...other props
/>

<DrawingComponent
    imageSrc={'image_path_2'}
    ...other props
/>

<DrawingComponent
    imageSrc={'image_path_3'}
    ...other props
/>
```

All 3 sketch canvas is displaying "image_path_1". Inspected the image and I noticed that it uses id="background" for all the canvas. Is this a bug? or there's some configuration that I missed?

Thank you.


