Writable books with both writable and written book components prioritize the written book component

Trying to create a book and quill containing both writable_book_content and written_book_content components using commands deletes the writable_book_content component, even though this is the component meant to be primarily used by writable books, not written_book_content.

How to reproduce:

1. Execute the following command:

   /give @s minecraft:writable_book[minecraft:writable_book_content={pages:["Test page"]},minecraft:written_book_content={author:Mojira,title:MC-278043}]

2. While holding the book you were given, execute the following command:

   /data get entity @s SelectedItem

   → ❌ The writable_book_content component is not present on the item.

3. Open the book you were given.
   → ❌ The book is not editable, since the writable_book_content component is not present.

Expected result:

Writable books would prioritize the writable_book_content component over the written_book_content component.

Observed result:

Writable books prioritize the written_book_content component over the writable_book_content component.