Section Styles: Prevent flash of variation style updates.

This is fixed by preloading the styles.

Fixes #61589.
Fixes #6989.
See WordPress/gutenberg#63172.

Props aaronrobertshaw, andrewserong, ramonopoly.



git-svn-id: https://develop.svn.wordpress.org/trunk@58690 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/edit-form-blocks.php

@@ -72,6 +72,9 @@ static function ( $classes ) {
 	sprintf( '%s/autosaves?context=edit', $rest_path ),
 	'/wp/v2/settings',
 	array( '/wp/v2/settings', 'OPTIONS' ),
+	'/wp/v2/global-styles/themes/' . get_stylesheet(),
+	'/wp/v2/themes?context=edit&status=active',
+	'/wp/v2/global-styles/' . WP_Theme_JSON_Resolver::get_user_global_styles_post_id() . '?context=edit',
 );
 
 block_editor_rest_api_preload( $preload_paths, $block_editor_context );