fix

src/student/leaderboard/index.tsx

@@ -152,7 +152,7 @@ export default defineComponent({
                                   height="34px"
                                   fit="cover"
                                   round
-                                  src={n.userAvatar}
+                                  src={n.userAvatar || IconAvator}
                                 />
                                 <div class={styles.user}>
                                   <div class={styles.name}>{n.username}</div>