[jorgefilipecosta]

Follow-up to #14671 (https://core.trac.wordpress.org/changeset/64689).

This PR stops listing the resolved data_processing settings in the root index, the namespace indexes and OPTIONS responses. The option configures how the server processes a response, nothing reads it from the index, and it is new in 7.2, so it can still change before the release.

• WP_REST_Server::get_data_for_route() no longer adds data_processing to the endpoint data.
• The index test now asserts the key is absent.

Trac ticket: https://core.trac.wordpress.org/ticket/66372

Testing

Register a trivial endpoint that turns the processing off, for example as a mu-plugin:

add_action(
	'rest_api_init',
	function () {
		register_rest_route(
			'demo/v1',
			'/hello',
			array(
				'methods'             => 'GET',
				'callback'            => function () {
					return array( 'hello' => 'world' );
				},
				'permission_callback' => '__return_true',
				'data_processing'     => false,
			)
		);
	}
);

1. Run curl -X OPTIONS http://localhost:8889/wp-json/demo/v1/hello. On trunk the endpoint carries "data_processing":{"fields":false,"embed":false,"links":false}; with this PR it is {"methods":["GET"],"args":[]} only. The key disappears from http://localhost:8889/wp-json/demo/v1 and http://localhost:8889/wp-json/ the same way.
2. Run curl 'http://localhost:8889/wp-json/demo/v1/hello?_fields=nope'. It still returns {"hello":"world"} without _links, so the option itself keeps working.
3. Verify unit tests are passing:

npm run test:php -- --filter Tests_REST_Server

Drafted with AI assistance (Claude Code) and reviewed by me.

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[sadmansakibnadvi]

Followed the testing steps on 7.2-beta3-64990. data_processing is gone from the OPTIONS response, the /demo/v1 index and the root index, and ?_fields=nope still returns {"hello":"world"} without _links. Results on the ticket: https://core.trac.wordpress.org/ticket/66372