Networks and Sites: Lazy load site meta.

In [36566] a framework to lazily load metadata was introduced. This supported term and comment meta by default. In this commit, extends support for site ( blog ) meta. Site meta is not heavily used by core and is used by developers to extend multisite. In this change, `_prime_site_caches` and `WP_Site_Query` now call the new function `wp_lazyload_site_meta`. The function `wp_lazyload_site_meta` accepts an array of ids and adds them to the queue of metadata to be lazily loaded. The function `get_blogs_of_user` was updated to now lazily load site meta. 

Follow on from [55671].

Props spacedmonkey, johnjamesjacoby, peterwilsoncc, mukesh27.
Fixes #58185.
Built from https://develop.svn.wordpress.org/trunk@55747


git-svn-id: http://core.svn.wordpress.org/trunk@55259 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/user.php

@@ -1004,9 +1004,8 @@ function get_blogs_of_user( $user_id, $all = false ) {
 
 	if ( ! empty( $site_ids ) ) {
 		$args = array(
-			'number'                 => '',
-			'site__in'               => $site_ids,
-			'update_site_meta_cache' => false,
+			'number'   => '',
+			'site__in' => $site_ids,
 		);
 		if ( ! $all ) {
 			$args['archived'] = 0;