FIX: Ensure list model is loaded

This fixes an edge case, such as when browsing directly into a topic in the
Knowledge Explorer view, where when you click the back button and the list
model is not generated.

assets/javascripts/discourse/controllers/knowledge-explorer.js.es6

@@ -3,6 +3,7 @@ import Category from "discourse/models/category";
 import Topic from "discourse/models/topic";
 import { on } from "discourse-common/utils/decorators";
 import KnowledgeExplorer from "discourse/plugins/discourse-knowledge-explorer/discourse/models/knowledge-explorer";
+import { getOwner } from "@ember/application";
 
 function mergeCategories(results) {
   const categories = Category.list();
@@ -243,6 +244,14 @@ export default Ember.Controller.extend({
       } else {
         this.set("expandedFilters", false);
       }
+    },
+
+    returnToList() {
+      this.set("selectedTopic", null);
+      getOwner(this)
+        .lookup("router:main")
+        .transitionTo("knowledgeExplorer");
+      this.send("refreshModel");
     }
   }
 });

assets/javascripts/discourse/models/knowledge-explorer.js.es6

@@ -2,7 +2,7 @@ import { ajax } from "discourse/lib/ajax";
 import Topic from "discourse/models/topic";
 
 function getTopic(id) {
-  return ajax(`/t/${id}.json`);
+  return ajax(`/t/${id}.json?ke=true`);
 }
 
 export default {

assets/javascripts/discourse/templates/components/knowledge-explorer-topic.hbs

@@ -1,6 +1,8 @@
-{{#link-to 'knowledgeExplorer' (query-params topic=null) class='knowledge-explorer-nav-link return'}}
-  {{i18n 'knowledge_explorer.topic.back'}}
-{{/link-to}}
+{{d-button
+  label="knowledge_explorer.topic.back"
+  class="knowledge-explorer-nav-link return"
+  action=return
+}}
 
 <div class="topic-content">
   <h1>{{topic.title}}</h1>

assets/javascripts/discourse/templates/knowledge-explorer.hbs

@@ -55,7 +55,7 @@
       </div>
       {{#if selectedTopic}}
         {{#conditional-loading-spinner condition=isTopicLoading}}
-          {{knowledge-explorer-topic topic=topic}}
+          {{knowledge-explorer-topic topic=topic return=(action "returnToList")}}
         {{/conditional-loading-spinner}}
       {{else}}
         <div class="knowledge-explorer-results">

assets/stylesheets/common/knowledge-explorer.scss

@@ -147,7 +147,12 @@
     .knowledge-explorer-nav-link {
       font-weight: 700;
       &.return {
+        align-items: center;
+        background: none;
+        color: $tertiary;
+        display: inline-flex;
         font-size: $font-down-1;
+        padding: 0;
         &::before {
           content: "«";
           margin-right: 5px;