[frontend/tasks] fix call for task_user_can_submit

inginious/frontend/pages/tasks.py

@@ -172,7 +172,7 @@ def POST(self, courseid, taskid, isLTI):
         userinput = flask.request.form
         if "@action" in userinput and userinput["@action"] == "submit":
             # Verify rights
-            if not self.user_manager.task_can_user_submit(task, username, isLTI):
+            if not self.user_manager.task_can_user_submit(task, username, lti=isLTI):
                 return json.dumps({"status": "error", "title": _("Error"), "text": _("You are not allowed to submit for this task.")})
 
             # Retrieve input random and check still valid