Editor: Ensure preloading middleware JSON is correctly encoded.

Adds the appropriate JSON flags to `wp_json_encode()` to safely encode data for use in script tags.

Developed in WordPress/wordpress-develop#8145.

Props jonsurrell, bernhard-reiter, dmsnell, artpi, ankitkumarshah, abcd95, dilipbheda, sainathpoojary, shanemuir.
Fixes #62797.

Built from https://develop.svn.wordpress.org/trunk@60648


git-svn-id: https://core.svn.wordpress.org/trunk@59984 1a063a9b-81f0-0310-95a4-ce76da25c4cd

Author: sirreal

wp-includes/block-editor.php

@@ -766,7 +766,7 @@ function block_editor_rest_api_preload( array $preload_paths, $block_editor_cont
 		'wp-api-fetch',
 		sprintf(
 			'wp.apiFetch.use( wp.apiFetch.createPreloadingMiddleware( %s ) );',
-			wp_json_encode( $preload_data )
+			wp_json_encode( $preload_data, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )
 		),
 		'after'
 	);

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.9-alpha-60647';
+$wp_version = '6.9-alpha-60648';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.