FIX: only show the reply as new topic when user can actually reply as new topic

app/assets/javascripts/discourse/controllers/share.js.es6

@@ -6,6 +6,7 @@ export default Ember.Controller.extend({
   needs: ['topic'],
 
   title: Ember.computed.alias('controllers.topic.model.title'),
+  canReplyAsNewTopic: Ember.computed.alias('controllers.topic.model.details.can_reply_as_new_topic'),
 
   @computed('type', 'postNumber')
   shareTitle(type, postNumber) {

app/assets/javascripts/discourse/templates/share.hbs

@@ -14,9 +14,11 @@
     {{share-source source=s title=title action="share"}}
   {{/each}}
 
-  <div class='reply-as-new-topic'>
-    <a href {{action "replyAsNewTopic"}} aria-label='{{i18n 'post.reply_as_new_topic'}}' title='{{i18n 'post.reply_as_new_topic'}}'>{{fa-icon "plus"}}{{i18n 'topic.create'}}</a>
-  </div>
+  {{#if canReplyAsNewTopic}}
+    <div class='reply-as-new-topic'>
+      <a href {{action "replyAsNewTopic"}} aria-label='{{i18n 'post.reply_as_new_topic'}}' title='{{i18n 'post.reply_as_new_topic'}}'>{{fa-icon "plus"}}{{i18n 'topic.create'}}</a>
+    </div>
+  {{/if}}
 
   <div class='link'>
     <a href {{action "close"}} aria-label='{{i18n 'share.close'}}' title='{{i18n 'share.close'}}'>{{fa-icon "close"}}</a>