Minor extensibility for flagged posts

app/assets/javascripts/admin/components/flagged-post.js.es6

@@ -13,15 +13,18 @@ export default Ember.Component.extend({
     'flaggedPost.deleted'
   ],
 
+  canAct: Ember.computed.alias('actableFilter'),
+
   @computed('filter')
-  canAct(filter) {
+  actableFilter(filter) {
     return filter === 'active';
   },
 
   removeAfter(promise) {
     return promise.then(() => {
       this.attrs.removePost();
-    }).catch(() => {
+    }).catch(error => {
+      if (error._discourse_displayed) { return; }
       bootbox.alert(I18n.t("admin.flags.error"));
     });
   },

app/assets/javascripts/admin/templates/components/flagged-post.hbs

@@ -158,6 +158,6 @@
     {{plugin-outlet
       name="flagged-post-below-controls"
       tagName=""
-      args=(hash flaggedPost=flaggedPost canAct=canAct)}}
+      args=(hash flaggedPost=flaggedPost canAct=canAct actableFilter=actableFilter)}}
   </div>
 </div>