🐛 fix(exam): 修复盈亏率表头显示错误

- 修正盈亏率表头文本，移除错误数字"23423342424"

src/client/mobile/components/Exam/ExamCard.tsx

@@ -347,7 +347,7 @@ export default function ExamCard() {
             <div>持币</div>
             <div>价格</div>
             <div>收益(元)</div>
-            <div>盈亏率</div>
+            <div>盈亏率23423342424</div>
           </div>
 
           {/* 表格内容 */}