Fix config schema

Problem/Motivation

Because of a recent core change all tests are failing.

Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for honeypot.settings with the following errors: honeypot.settings:langcode missing schema in Drupal\Core\Config\Testing\ConfigSchemaChecker->onConfigSave() (line 98 of core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php).

This should be the core issue causing this change: #2541800: Some config do not inherit from config_object, so locale_system_set_config_langcodes() results in schema errors

Proposed resolution

Minor schema update