fix some ui issues

Author: IdirLISN

src/static/riot/competitions/detail/submission_manager.tag

@@ -204,13 +204,9 @@
             </button>
         </div>
 
-        <div style="display:flex; align-items:center; gap:8px;">
-            <label>Per page</label>
-            <select class="ui dropdown" value="{ page_size }" onchange="{ change_page_size.bind(this) }">
-                <option value="20">20</option>
-            </select>
+        <div style="display:flex; align-items:center; gap:8px; margin-left: auto;">
 
-            <div style="margin-left:10px; color: #8c8c8c;">
+            <div style="margin-right: 10px; color: #8c8c8c;">
                 <small>{ total_count || 0 } total</small>
             </div>
     </div>