Toolbar: Show the Customize link on front end when using a block theme if any plugins use the Customizer.

In WordPress 5.9, when a block theme is being used, the `Appearance → Customize` admin menu item is not present unless a plugin uses the Customizer.

The Customize admin bar node should be shown on the front end if any plugins are using the Customizer, even if the current theme is a block theme.

This commit mirrors a similar check in the admin menu to determine if the Customize link should be displayed.

Follow-up to [52069], [52134], [52158], [52178].

Props pbiron, audrasjb, sabernhardt, costdev.
Fixes #54683.
Built from https://develop.svn.wordpress.org/trunk@52414


git-svn-id: http://core.svn.wordpress.org/trunk@52006 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/admin-bar.php

@@ -446,8 +446,8 @@ function wp_admin_bar_edit_site_menu( $wp_admin_bar ) {
 function wp_admin_bar_customize_menu( $wp_admin_bar ) {
 	global $wp_customize;
 
-	// Don't show if a block theme is activated.
-	if ( wp_is_block_theme() ) {
+	// Don't show if a block theme is activated and no plugins use the customizer.
+	if ( wp_is_block_theme() && ! has_action( 'customize_register' ) ) {
 		return;
 	}
 

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-beta4-52413';
+$wp_version = '5.9-beta4-52414';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.