remove default emoji

client/src/components/LeaderboardSection/components/LeaderboardCard.jsx

@@ -52,14 +52,14 @@ const LeaderboardCard = ({ leaderboard }) => {
 
   // Récupérer uniquement le dernier emoji
   const getLastEmoji = () => {
-    if (!card_data.emoji) return "🎯";
+    if (!card_data.emoji) return null;
 
     // Utiliser GraphemeSplitter pour diviser correctement les emojis
     const splitter = new GraphemeSplitter();
     const graphemes = splitter.splitGraphemes(card_data.emoji);
 
     // Retourner le dernier graphème (emoji)
-    return graphemes.length > 0 ? graphemes[graphemes.length - 1] : "🎯";
+    return graphemes.length > 0 ? graphemes[graphemes.length - 1] : null;
   };
 
   const lastEmoji = getLastEmoji();
@@ -257,7 +257,7 @@ const LeaderboardCard = ({ leaderboard }) => {
                   card_data.title || leaderboard.id
                 )}
               </Typography>
-              <Box sx={{ fontSize: "1.5rem" }}>{lastEmoji}</Box>
+              {lastEmoji && <Box sx={{ fontSize: "1.5rem" }}>{lastEmoji}</Box>}
             </Box>
             {displayDescription && (
               <Typography