admins: remove some order column because too slow

app/views/admins/user_statistics/shared/_list.html.erb

@@ -3,8 +3,8 @@
   <tr>
     <th width="14%" class="text-left">姓名</th>
     <th width="22%" class="text-left">单位部门</th>
-    <th width="10%"><%= sort_tag('学习关卡数', name: 'study_challenge_count', path: admins_user_statistics_path) %></th>
-    <th width="10%"><%= sort_tag('完成关卡数', name: 'finish_challenge_count', path: admins_user_statistics_path) %></th>
+    <th width="10%">学习关卡数<%#= sort_tag('学习关卡数', name: 'study_challenge_count', path: admins_user_statistics_path) %></th>
+    <th width="10%">完成关卡数<%#= sort_tag('完成关卡数', name: 'finish_challenge_count', path: admins_user_statistics_path) %></th>
     <th width="10%"><%= sort_tag('学习实训数', name: 'study_shixun_count', path: admins_user_statistics_path) %></th>
     <th width="10%"><%= sort_tag('完成实训数', name: 'finish_shixun_count', path: admins_user_statistics_path) %></th>
     <th width="10%">评测次数</th>