Themes: Ensure `WP_Theme::get_files()` doesn't return unexpected values.

This change filters out empty entries from `WP_Theme::get_files()` before returning the array of files. This avoid returning an entry with `false` value when the directory of the theme does not exist.

Props dd32, opurockey, Rahmohn, audrasjb.
Fixes #53599.

Built from https://develop.svn.wordpress.org/trunk@53253


git-svn-id: http://core.svn.wordpress.org/trunk@52842 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-theme.php

@@ -1210,7 +1210,7 @@ final class WP_Theme implements ArrayAccess {
 			$files += (array) self::scandir( $this->get_template_directory(), $type, $depth );
 		}
 
-		return $files;
+		return array_filter( $files );
 	}
 
 	/**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0-beta2-53252';
+$wp_version = '6.0-beta2-53253';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.