`useRootPaddingAwareAlignments` is missing from theme.json schema

[mikachan]

Description

The useRootPaddingAwareAlignments key is missing from the theme.json schema. We should include this to maintain a good developer experience when working with theme.json files.

More info about this setting: #42085, #43463

Step-by-step reproduction instructions

1. Activate a theme with a theme.json file and open the theme.json
2. Add "useRootPaddingAwareAlignments": true under settings
3. Notice that the JSON schema is unaware of this key

Screenshots, screen recording, code snippet

Environment info

WP 6.0.1, GB trunk, Twenty Twenty-Three

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