Schema error `add_classes` missing

I installed the module manually and added the `Smart Range Field` field in my dev environment and it worked fine as expected then i tried to export the config from `admin/config/development/configuration/single/export` the files and its storage ex: (field.field.node.event.field_date.yml, field.storage.node.field_date) and added it as inside `test_module`module install folder and run it as part of unit testing ex : php ./core/scripts/run-tests.sh --verbose --suppress-deprecations --color --url 'http://local.com' --php "$(which php)" --class 'Drupal\Tests\test_module\Functional\Sampletest' it comes up with couple of schema errors

    Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for
     Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for
    core.entity_view_display.node.event.tile_large with the following errors:
    core.entity_view_display.node.event.tile_large:content.field_event_date.settings.add_classes
    missing schema

Seems like we need to add the below in schema

    add_classes:
      type: integer
      label: 'Add Class'
      translation context: 'Add classed spans around the time and date values.'

in `smart_date.schema.yml` under `field.formatter.settings.smartdate_default:`