Uncaught TypeError: Cannot read properties of null (reading 'append')

[EddyVinck]

Describe the bug
Copy pasting something in the editor into an empty block doesn't work. It is a problem on my localhost + in one of the demos on the website.

To Reproduce

1. Open the StackBlitz link from this example https://www.blocknotejs.org/docs/editor-basics/default-schema
2. try coping some text from outside the editor and pasting it (this works)
3. try copying some block from the Blocknote editor and pasting it (see error)

blocknote-copy-paste-bug.mp4

Misc

• Node version: stackblitz default
• Package manager: stackblitz default
• Browser: Arc / Chromium
• I'm a sponsor and would appreciate if you could look into this sooner than later 💖

[EddyVinck]

This is a duplicate of #1648, which is a part of #1645