Learnpath: Avoid calling function if the object does not existe to avoid error logs on a NULL value -refs BT#20099

main/lp/learnpathItem.class.php

@@ -4114,7 +4114,9 @@ class learnpathItem
         }
 
 	// It updates the last progress only in case.
+        if (is_object($_SESSION['oLP'])) {
             $_SESSION['oLP']->updateLpProgress();
+        }
 
         if ($debug) {
             error_log('End of learnpathItem::write_to_db()', 0);