display language name in user locale selector - make it consistent with admin (#5424)

app/assets/javascripts/discourse/controllers/preferences/interface.js.es6

@@ -33,7 +33,7 @@ export default Ember.Controller.extend(PreferencesTabController, {
 
   @computed()
   availableLocales() {
-    return this.siteSettings.available_locales.split('|').map(s => ({ name: s, value: s }));
+    return JSON.parse(this.siteSettings.available_locales);
   },
 
   @computed()

app/models/site_setting.rb

@@ -30,7 +30,7 @@ class SiteSetting < ActiveRecord::Base
   client_settings << :available_locales
 
   def self.available_locales
-    LocaleSiteSetting.values.map { |e| e[:value] }.join('|')
+    LocaleSiteSetting.values.to_json
   end
 
   def self.topic_title_length