Description

Unlinking Submenu block causes empty href attribute on front of site.

Step-by-step reproduction instructions

1. Add Nav block.
2. Add Submenu with a link and add one item inside the submenu.
3. Click on Submenu block and click the link icon.
4. Remove the link from the block using the "Unlink" icon in the Link UI.
5. Publish post.
6. Switch to front of site and see empty href on the submenu item in the Nav.

Screenshots, screen recording, code snippet

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes