Fixed all settings appearing in home and post groups

refs f4596a0add

- when extracting the groups code from component to service some variable names were changed but the assignment was missed meaning we were assigning all settings rather than specific group settings to each `group.settings` array

ghost/admin/app/services/custom-theme-settings.js

@@ -102,7 +102,7 @@ export default class CustomThemeSettingsServices extends Service {
             const groupSettings = settings.filter(setting => setting.group === knownGroup.key);
 
             if (groupSettings.length) {
-                groups.push(Object.assign({}, knownGroup, {settings}));
+                groups.push(Object.assign({}, knownGroup, {settings: groupSettings}));
             }
         });