Theme.json: Fix schema for useRootPaddingAwareAlignments

[t-hamano]

Fix #43624
Follow-up on #43463

What?

This PR fixes a problem in theme.json where the settings.useRootPaddingAwareAlignments key is not allowed in the schema and enables autocompletion.

Why?

This is because a definition for this property exists but does not refer to it.

How?

Added references to existing definitions.

Such references may seem strange, but in order to automatically generate theme.json living reference, each section of definitions must have a properties key even if the type is a boolean value. Therefore, I followed the tree of definitions to refer to the correct definition.

Testing Instructions

Create a JSON file that references the JSON schema for this branch, such as:

{
	"$schema": "https://raw.githubusercontent.com/WordPress/gutenberg/fix/theme-json-schema-root-padding/schemas/json/theme.json",
	"version": 2,
	"settings": {
	}
}

Under the settings property, confirm that the key is included in the candidates.

confirm that the key is not allowed lower down in the hierarchy.

[mikachan]

Thank you! Works well for me: