Title block doesn't respect "Disable new blocks" restriction from DX Layout

[avoinea]

Describe the bug

Title-Layout.webm

To Reproduce

1. Go to ControlPanel > Content Types
2. Add new content type: Book
3. Go to Layout for Book and enable editable blocks
4. Click on Title block and then on Settings in the Sidebar
5. Select "Disable new blocks" you will notice the "+" disappears and Save
6. Go to Home Page and add a new Book
7. Fill the Title block and press Enter.

Expected behavior A new block should not be created when you press Enter in the Title block if it has "Disable new blocks"

Screenshots If applicable, add screenshots to help explain your problem.

Software (please complete the following information):

• OS: macOS
• Browser Chrome
• Volto Version 18.0.0-alpha.43
• Plone Version 6.0.13
• Plone REST API Version 9.7.2

Additional context