FIX: show update banner only once on categories with subcategory lists (#17782)

* FIX: show update banner only once on categories with subcategory lists

app/assets/javascripts/discourse/app/controllers/discovery/categories.js

@@ -23,6 +23,10 @@ export default DiscoveryController.extend({
   category: null,
 
   canEdit: reads("currentUser.staff"),
+  @discourseComputed
+  isCategoriesRoute() {
+    return this.router.currentRouteName === "discovery.categories";
+  },
   @discourseComputed("model.parentCategory")
   categoryPageStyle(parentCategory) {
     let style = this.siteSettings.desktop_category_page_style;

app/assets/javascripts/discourse/app/templates/discovery/categories.hbs

@@ -1,7 +1,7 @@
 <PluginOutlet @name="above-discovery-categories" @connectorTagName="div" @args={{hash categories=this.model.categories categoryPageStyle=this.categoryPageStyle topics=this.model.topics}} />
 
 <DiscoveryCategories @refresh={{action "refresh"}}>
-  {{#if this.topicTrackingState.hasIncoming}}
+  {{#if (and this.topicTrackingState.hasIncoming this.isCategoriesRoute)}}
     <div class="show-more {{if this.hasTopics "has-topics"}}">
       <div role="button" class="alert alert-info clickable" {{action "showInserted"}}>
         <CountI18n @key="topic_count_" @suffix={{this.topicTrackingState.filter}} @count={{this.topicTrackingState.incomingCount}} />