Description

Fixes #22626

Implements the 'block selection clearing' feature in the Navigation Editor.

What is it? In the post and site editor, when clicking in the empty editor canvas blocks are deselected. This feature wasn't present in the Navigation Editor.

Because block selection determines whether a sub-menu is open, it was a bit hard to close sub-menus in the navigation editor, which this solves.

This has required a bit of CSS wrangling as previously the block editor part of the Navigation Editor had a lot of margin around it, and collapsed to the height of its content leaving no empty clickable area.

How has this been tested?

1. Open the navigation editor
2. Make a menu with submenus
3. Click on a block with a submenu to open that submenu
4. Click the editor canvas, observe the menu should close and the block become deselected.

Screenshots

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.