Copying to clipboard of react custom blocks that use context #592
Description
Copying the React Alert demo block doesn't work, because it's render function relies on React Context (for dropdown menu).
Overriding toExternalHtml doesn't suffice, because we also call toInternalHtml to set the blocknote data on the clipboard. However, toInternalHTML always calls render(), which depends on the React Context.
We need to review to usage of toInternalHTML and see if it needs to be customizable