fix(contest): pass current user ID in leaderboard query

Add user_id parameter to leaderboard query in contest route to
support tests relying on current user context. This change ensures
test scenarios can simulate authenticated user behavior since
Mirage lacks an auth context.

Author: rohitpaulk

app/routes/contest.ts

@@ -137,6 +137,7 @@ export default class ContestRoute extends BaseRoute {
         include: 'leaderboard,user',
         leaderboard_id: model.contest.leaderboard.id,
         filter_type: 'around_me',
+        user_id: this.authenticator.currentUserId, // Only used in tests since mirage doesn't have auth context
       })) as unknown as LeaderboardEntryModel[];
     }
   }