Fixed members count in confirm email modal

no issue

- the members count used to disable the email toggle and shown in the confirm modal was incorrect as it didn't take into account subscribed vs non-subscribed members
- adjusts the filter in the count query to only fetch subscribed members

app/controllers/editor.js

@@ -547,7 +547,7 @@ export default Controller.extend({
     // load supplementel data such as the members count in the background
     backgroundLoader: task(function* () {
         if (this.feature.members) {
-            let membersResponse = yield this.store.query('member', {limit: 1});
+            let membersResponse = yield this.store.query('member', {limit: 1, filter: 'subscribed:true'});
             this.set('memberCount', get(membersResponse, 'meta.pagination.total'));
         }
     }).restartable(),