Made Portal preview scrollable

- Updated Portal preview in Membership settings and Portal settings so that the preview is scrollable in all browsers.

Note: Only when Tiers is turned on.

ghost/admin/app/components/modal-portal-settings.hbs

@@ -317,7 +317,7 @@
             <div class="gh-portal-preview-container {{if this.showLinksPage "hide"}}">
                 <div class="gh-portal-site-frame-cover"> </div>
                 <GhSiteIframe
-                    class="gh-portal-siteiframe"
+                    class="gh-portal-siteiframe {{if (feature "multipleProducts") "gh-portal-siteiframe-enabled"}}"
                     @src={{this.portalPreviewUrl}}
                     @guid={{this.portalPreviewGuid}}
                     @invisibleUntilLoaded="portal-ready" />

ghost/admin/app/styles/layouts/portal-settings.css

@@ -356,6 +356,10 @@
     height: calc((1 / 0.95) * 100%) !important;
 }
 
+.gh-portal-siteiframe-enabled {
+    pointer-events: unset;
+}
+
 .gh-portal-site-frame-cover {
     position: absolute;
     top: 0;

ghost/admin/app/styles/layouts/settings.css

@@ -1596,6 +1596,10 @@ p.theme-validation-details {
     transition: height 0.17s ease-out;
 }
 
+.gh-setting-members-portal-mock.mock-enabled {
+    pointer-events: unset;
+}
+
 .gh-setting-members-portal-disabled {
     display: flex;
     flex-direction: column;

ghost/admin/app/templates/settings/membership.hbs

@@ -47,7 +47,7 @@
                 </div>
             </div>
             <div class="gh-setting-members-portalpreview">
-                <div class="gh-setting-members-portal-mock">
+                <div class="gh-setting-members-portal-mock {{if (feature "multipleProducts") "mock-enabled"}}">
                     {{#if (or (eq this.settings.membersSignupAccess 'none') this.switchFromNoneTask.isRunning)}}
                         <div class="gh-setting-members-portal-disabled">
                             <span class="lightgrey">{{svg-jar "portal-logo-stroke"}}</span>