BUGFIX: properly hide categories/top lists view when loading another tab

app/assets/javascripts/discourse/templates/list/categories.js.handlebars

@@ -1,4 +1,5 @@
-<div class='contents'>
+{{#if model.categories}}
+  <div class='contents'>
     <table id='topic-list' class='categories'>
       <thead>
         <tr>
@@ -97,6 +98,6 @@
         {{/each}}
       </tbody>
     </table>
-</div>
-<footer id='topic-list-bottom'></footer>
-
+  </div>
+  <footer id='topic-list-bottom'></footer>
+{{/if}}

app/assets/javascripts/discourse/templates/list/top.js.handlebars

@@ -1,4 +1,5 @@
-<div class="top-lists">
+{{#if content}}
+  <div class="top-lists">
     {{#if redirectedToTopPageReason}}
       <div class="alert alert-info">
         {{redirectedToTopPageReason}}
@@ -45,4 +46,5 @@
       {{/if}}
       </h3>
     </footer>
-</div>
+  </div>
+{{/if}}