Query Exception when configuring ReadonlyFieldWidget for Field

Problem/Motivation

We are encountering the following error when configuring a Field from Registration Type to the Widget from Module "readonly_field_widget".

Drupal\Core\Database\InvalidQueryException: Query condition 'registration_settings_field_data.entity_id IN ()' cannot be empty. in Drupal\Core\Database\Query\Condition->condition() (line 108 of core/lib/Drupal/Core/Database/Query/Condition.php).

Drupal\Core\Database\Query\Select->condition('registration_settings_field_data.entity_id', Array, 'IN') (Line: 77)
Drupal\Core\Entity\Query\Sql\Condition->compile(Object) (Line: 177)
Drupal\Core\Entity\Query\Sql\Query->compile() (Line: 82)
Drupal\Core\Entity\Query\Sql\Query->execute() (Line: 614)
Drupal\Core\Entity\EntityStorageBase->loadByProperties(Array) (Line: 56)
Drupal\registration\RegistrationSettingsStorage->loadSettingsForHostEntity(Object) (Line: 617)
Drupal\registration\HostEntity->getSettings() (Line: 315)
Drupal\registration\HostEntity->getCacheContexts() (Line: 171)
Drupal\Core\Cache\CacheableMetadata::createFromObject(Object) (Line: 54)
Drupal\registration\Plugin\Field\FieldFormatter\RegistrationTypeFormatter->viewElements(Object, 'de') (Line: 91)
Drupal\Core\Field\FormatterBase->view(Object, 'de') (Line: 268)
Drupal\Core\Entity\Entity\EntityViewDisplay->buildMultiple(Array) (Line: 226)
Drupal\Core\Entity\Entity\EntityViewDisplay->build(Object) (Line: 461)
Drupal\Core\Entity\EntityViewBuilder->viewField(Object, Array) (Line: 120)
Drupal\readonly_field_widget\Plugin\Field\FieldWidget\ReadonlyFieldWidget->formElement(Object, 0, Array, Array, Object) (Line: 459)
Drupal\Core\Field\WidgetBase->formSingleElement(Object, 0, Array, Array, Object) (Line: 85)
Drupal\readonly_field_widget\Plugin\Field\FieldWidget\ReadonlyFieldWidget->formMultipleElements(Object, Array, Object) (Line: 120)
Drupal\Core\Field\WidgetBase->form(Object, Array, Object) (Line: 287)
Drupal\Core\Field\FieldItemList->defaultValuesForm(Array, Object) (Line: 35)
Drupal\registration\Plugin\Field\RegistrationItemFieldItemList->defaultValuesForm(Array, Object) (Line: 230)
Drupal\field_ui\Form\FieldConfigEditForm->form(Array, Object) (Line: 107)
Drupal\Core\Entity\EntityForm->buildForm(Array, Object)
call_user_func_array(Array, Array) (Line: 536)
Drupal\Core\Form\FormBuilder->retrieveForm('field_config_edit_form', Object) (Line: 284)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object) (Line: 73)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 181)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 53)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 32)
Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 116)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 90)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 741)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

We already debugged this and the "HostEntityInterface" in "RegistrationSettingsStorage::loadSettingsForHostEntity" has no ID.

Steps to reproduce

• Install Module readonly_field_widget
• Create some Node Bundle with a Registration field type.
• Configure this field to use the "ReadonlyFieldWidget" unter "...../form-display".
• Naviate back to "...../fields" and klick on "Edit" for the field.