Return 404 if not yet access to submission data

Note that we do this check before verifying the existence of team or
problem, s.t. we do not leak any information.

Author: Kevinjil

webapp/src/Controller/PublicController.php

@@ -330,6 +330,11 @@ public function submissionsDataAction(Request $request, ?string $teamId, ?string
         }
 
         $scoreboard = $this->scoreboardService->getScoreboard($contest);
+
+        if (!$scoreboard) {
+            throw $this->createNotFoundException('No submission data found');
+        }
+
         $teamIds = array_map(fn(Team $team) => $team->getTeamid(), $scoreboard->getTeamsInDescendingOrder());
 
         /** @var Submission[] $submissions */