Locales helper improvement

Added a rescue block in `name_for_locale()` to ensure the application doesn't crash in case it receives an invalid locale.

app/helpers/locales_helper.rb

@@ -3,6 +3,8 @@ module LocalesHelper
   def name_for_locale(locale)
     default = I18n.t("locale", locale: locale)
     I18n.backend.translate(locale, "i18n.language.name", default: default)
+  rescue
+    nil
   end
 
-end
+end