Support site_intent for /me/sites endpoint

Summary:
As we need to show different support articles according to the site intent, add `site_intent` into options list so that we can query from the `/me/sites` endpoint

Related to Automattic/wp-calypso#58486

Test Plan:
1. Go to https://[private link]
2. Select WP.COM API > v1.2
3. Use `/me/sites?fields=options&options=site_intent`
4. Check the response of sites contains `site_intent`

Also, you can follow the testing instructions from Automattic/wp-calypso#58486

Reviewers: #ganon_team, philipmjackson

Reviewed By: #ganon_team, philipmjackson

Subscribers: philipmjackson

Tags: #touches_jetpack_files

Differential Revision: D70637-code

This commit syncs r235663-wpcom.

projects/plugins/jetpack/json-endpoints/class.wpcom-json-api-get-site-endpoint.php

@@ -157,6 +157,7 @@ class WPCOM_JSON_API_GET_Site_Endpoint extends WPCOM_JSON_API_Endpoint {
 		'is_cloud_eligible',
 		'selected_features',
 		'anchor_podcast',
+		'site_intent',
 	);
 
 	protected static $jetpack_response_field_additions = array(
@@ -669,6 +670,9 @@ protected function render_option_keys( &$options_response_keys ) {
 				case 'anchor_podcast':
 					$options[ $key ] = $site->get_anchor_podcast();
 					break;
+				case 'site_intent':
+					$options[ $key ] = $site->get_site_intent();
+					break;
 			}
 		}
 

projects/plugins/jetpack/sal/class.json-api-site-base.php

@@ -726,4 +726,11 @@ public function get_selected_features() {
 	public function get_anchor_podcast() {
 		return get_option( 'anchor_podcast' );
 	}
+
+	/**
+	 * Get the option of site intent which value is coming from the Hero Flow
+	 */
+	public function get_site_intent() {
+		return get_option( 'site_intent', '' );
+	}
 }