Cannot copy paste text with images from word files anymore due to a JS error

Steps to reproduce

1. Open a .doc, .docx or .rtf file containing text with image(s)
2. Copy some text including one or more images at the same time
3. Edit a page in-place or in WYSIWYG mode
4. Press CTRL + V

Expected results

The whole content is pasted properly into wiki page, text with image(s).

Actual results

Nothing is pasted. In the browser's console, the following error is displayed:

Uncaught TypeError: Cannot read properties of undefined (reading 'split')
    at b.uploadRepository.create (ckeditor.js:1605:130)
    at f.<anonymous> (ckeditor.js:1444:499)
    at f.l (ckeditor.js:10:246)
    at f.<anonymous> (ckeditor.js:12:91)
    at window.CKEDITOR.window.CKEDITOR.dom.CKEDITOR.editor.CKEDITOR.editor.fire (ckeditor.js:13:285)
    at ckeditor.js:1296:190
    at Object.<anonymous> (ckeditor.js:1295:361)
    at Object.callback (ckeditor.js:251:178)
    at n (ckeditor.js:249:111)
    at Array.p (ckeditor.js:249:266)

The issue does not reproduce when the text or image(s) are copied separately and could not be reproduced on XWiki 14.10.11 or 15.4.

The issue was reproduced initially by Lucian.