Editor: Use a non-persistent object cache instead of transient in wp_get_global_stylesheet().

This changeset is part of a greater effort to enhance the caching strategy for `theme.json` based data. Similar to [55138], the cache is currently ignored when `WP_DEBUG` is on to avoid interrupting the theme developer's workflow.

Props oandregal, spacedmonkey, hellofromtonya, flixos90, ironprogrammer, azaozz, aristath, costdev, mcsf.
Fixes #56910.

Built from https://develop.svn.wordpress.org/trunk@55148


git-svn-id: http://core.svn.wordpress.org/trunk@54681 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/load.php

@@ -753,7 +753,7 @@ function wp_start_object_cache() {
 			)
 		);
 
-		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );
+		wp_cache_add_non_persistent_groups( array( 'counts', 'plugins', 'theme_json' ) );
 	}
 
 	$first_init = false;