Fixed lib_test to succeed

Co-authored-by: mantarias <mantas2630@hotmail.com>

server/moodle/mod/livequiz/tests/phpunit/lib_test.php

@@ -41,6 +41,7 @@ protected function setUp(): void {
      * It should return false if the instance cannot be added.
      */
     public function test_livequiz_add_instance(): void {
+        require_once(__DIR__ . '/../../lib.php');
         global $DB;
 
         $quizdata = new \stdClass(); // Create a new stdClass object (empty object).