Editor: Use wp_add_inline_script() instead of wp_localize_script() to pass the _wpMetaBoxUrl value to the wp-editor script.

This fixes a PHP 8 "Only the first byte will be assigned to the string offset" warning on Edit Post screen.

The correct usage of `wp_localize_script()` is to pass an array of data, not a string.

Fixes #51108.

git-svn-id: https://develop.svn.wordpress.org/trunk@48841 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -125,7 +125,11 @@ $meta_box_url = add_query_arg(
 	),
 	$meta_box_url
 );
-wp_localize_script( 'wp-editor', '_wpMetaBoxUrl', $meta_box_url );
+wp_add_inline_script(
+	'wp-editor',
+	sprintf( 'var _wpMetaBoxUrl = %s;', wp_json_encode( $meta_box_url ) ),
+	'before'
+);
 
 
 /*