fix: Publisher::discover() may loads incorrect classname

Author: kenjis

system/Publisher/Publisher.php

@@ -111,9 +111,9 @@ final public static function discover(string $directory = 'Publishers'): array
 
         // Loop over each file checking to see if it is a Publisher
         foreach (array_unique($files) as $file) {
-            $className = $locator->findQualifiedNameFromPath($file);
+            $className = $locator->getClassname($file);
 
-            if (is_string($className) && class_exists($className) && is_a($className, self::class, true)) {
+            if ($className !== '' && class_exists($className) && is_a($className, self::class, true)) {
                 self::$discovered[$directory][] = new $className();
             }
         }