Editor: Prevent block-editor JavaScript loading in other editors.

Add a check to `wp_add_iframed_editor_assets_html()` confirming the edit post screen is using the block-editor before including block-editor specific JavaScript. For the classic and other editors the function returns early without any output.

Props swissspidy, desrosj.
Fixes #53696.


Built from https://develop.svn.wordpress.org/trunk@51540


git-svn-id: http://core.svn.wordpress.org/trunk@51151 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/script-loader.php

@@ -2732,6 +2732,10 @@ function wp_maybe_inline_styles() {
  * @since 5.8.0
  */
 function wp_add_iframed_editor_assets_html() {
+	if ( ! wp_should_load_block_editor_scripts_and_styles() ) {
+		return;
+	}
+
 	$script_handles = array();
 	$style_handles  = array(
 		'wp-block-editor',

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51539';
+$wp_version = '5.9-alpha-51540';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.