Description

Fixes #36427 and #36439.

The background colour classnames weren't rendering on the front end due to a attribute name error in the block PHP.

How has this been tested?

In a Navigation block with nested Submenus, change the Overlay background colour to a non-default value. Make sure the Background colour value is set to default. Publish and check that overlay background colour applies to all the submenus on the front end.

Screenshots

Types of changes

Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• 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 (please manually search all *.native.js files for terms that need renaming or removal).