Fix broken exception class usage

Author: marcelfolaron

app/Domain/Notifications/Services/News.php

@@ -8,8 +8,6 @@
     use Leantime\Domain\Setting\Services\Setting;
     use Leantime\Domain\Users\Repositories\Users as UserRepository;
 
-    use function PHPUnit\Framework\throwException;
-
     /**
      * @api
      */
@@ -101,7 +99,7 @@ public function getFeed()
             if (function_exists('simplexml_load_string')) {
                 $responseXml = simplexml_load_string($response);
             } else {
-                throwException("Simple XML load string function doesn't exists");
+                throw new \Exception("Simple XML extension is not installed");
             }
 
             return $responseXml;