Remove setting due to static method in Drupal Core

That error pops up when saving:
Error: Using $this when not in object context in Drupal\link_no_protocol\Plugin\Field\FieldWidget\NoProtocolLinkWidget::getUserEnteredStringAsUri()

Because the drupal core widget declares a method as static, it prevents us to use a setting to enable or disable. Anyway, it was kind of useless anyway because the behavior is the same as default when the feature is disabled.