CourseDateDecorator: fixed coures_sem_type_id field output

classes/decorators/CourseDateDecorator.class.php

@@ -205,7 +205,7 @@ class CourseDateDecorator extends Decorator
             }
             $result[$this->fields['course_full_name']->getDisplayName()] = $course_full_name;
         }
-        if (in_array('course_sem_type_id', $this->enabled_decorated_fields)) {
+        if ($this->fields['course_sem_type_id']->isEnabled()) {
             $sem_type_id = '';
             if ($course_date->course instanceof \Course) {
                 $sem_type_id = $course_date->course->status;