Widgets: Add missing label and description to Customizer controls.

This fixes a bug where the “Move To” dialogue was empty when a theme has multiple widget areas.

Props kevin940726, noisysocks, hellofromTonya.
Fixes #53487.

git-svn-id: https://develop.svn.wordpress.org/trunk@51228 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-customize-widgets.php

@@ -480,8 +480,10 @@ final class WP_Customize_Widgets {
 							$this->manager,
 							$setting_id,
 							array(
-								'section'    => $section_id,
-								'sidebar_id' => $sidebar_id,
+								'section'     => $section_id,
+								'sidebar_id'  => $sidebar_id,
+								'label'       => $section_args['title'],
+								'description' => $section_args['description'],
 							)
 						);
 					} else {