It throws a JS error when I copy and paste an image inside the richtext editor in Ibexa 4.5.0.

I also have Ibexa 4.4.1 installation where it works and there's no error.

To reproduce the problem:

1. Create/edit a content that have a richtext attribute
2. In the richtext toolbar use Image Embed and embed some image
3. Select image in the richtext editor, copy and paste it

Result: Image is not pasted and we get an error in the javascript console

The error is thrown in the fieldtype-richtext bundle in the file `src/bundle/Resources/public/js/CKEditor/embed/image/embed-image-editing.js` at line 174.

The object `link` doesn't have a function `getAttribute` so it fails trying to execute this line

upcastWriter.setAttribute('ibexaLinkHref', link.getAttribute('href'), modelElement);

When I change the condition at line 173 to

if (link && link.getAttribute) {

then copy & paste of an image works fine and there's no error.