Added option to show empty terms

[pbearne]

Fixes #35489

Description

Add an option to show empty terms

Screenshots

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

• [ x] My code is tested.
• [x ] My code follows the WordPress code style.
• [x ] My code follows the accessibility standards.
• [ x] I've tested my changes with keyboard and screen readers.
• [ x] My code has proper inline documentation.
• [x ] 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).

[carolinan]

Hi @pbearne!
I tried to re-run the tests, but was not able to. I think the failing tests may be related to the test fixtures, which needs to be updated because of the added attributes in block.json.

[skorasaurus]

Thanks for your initial work on this; it was completed in #39426