Updated frontend helpers to handle tiers visibility

refs https://github.com/TryGhost/Team/issues/1071

- visibility handling for posts/pages with restricted tiers access has changed, this change updates frontend helpers

core/frontend/helpers/prev_post.js

@@ -27,7 +27,7 @@ const buildApiOptions = function buildApiOptions(options, post) {
         /**
          * @deprecated: single authors was superceded by multiple authors in Ghost 1.22.0
          */
-        include: 'author,authors,tags',
+        include: 'author,authors,tags,tiers',
         order: 'published_at ' + order,
         limit: 1,
         // This line deliberately uses double quotes because GQL cannot handle either double quotes

core/frontend/helpers/products.js

@@ -6,7 +6,6 @@
 const {labs} = require('../services/proxy');
 const {SafeString} = require('../services/rendering');
 
-const nql = require('@nexes/nql');
 const isString = require('lodash/isString');
 
 function products(options = {}) {
@@ -29,11 +28,8 @@ function products(options = {}) {
         accessProductsList = productsList;
     }
 
-    if (this.visibility === 'filter') {
-        const nqlFilter = nql(this.visibility_filter);
-        accessProductsList = productsList.filter((product) => {
-            return nqlFilter.queryJSON({product: product.slug});
-        });
+    if (this.visibility === 'tiers') {
+        accessProductsList = this.tiers;
     }
 
     if (accessProductsList.length > 0) {

core/frontend/helpers/tpl/content-cta.hbs

@@ -7,7 +7,7 @@
         {{#has visibility="members"}}
             <h2>This post is for subscribers only</h2>
         {{/has}}
-        {{#has visibility="filter"}}
+        {{#has visibility="tiers"}}
             <h2>This post is for subscribers on the {{products}} only </h2>
         {{/has}}
         {{#if @member}}