Fix compatibility issue with Custom Field

Problem/Motivation

I wanted to install Custom Field module, when I realized was already required by this starterkit. But I can not update to the next version nor remove the Organization Starterkit module.

Steps to reproduce

• Install Schema.org Blueprints: Organization Starterkit with composer: composer require 'drupal/schemadotorg_starterkit_organization:^1.0@alpha'. No need to enable the module
• Try installing Custom Field with composer: composer require 'drupal/custom_field:^4.0@RC'
• Composer installation will give an error
• Then remove the starterkit from composer: composer remove drupal/schemadotorg_starterkit_organization
• After successfully removing the starterkit I get a page error

The website encountered an unexpected error. Try again later.

Drupal\Component\Plugin\Exception\PluginNotFoundException: Unable to determine class for field type 'entity_reference_override' found in the 'field.storage.node.schema_provider' configuration in Drupal\field\FieldStorageConfigStorage->mapFromStorageRecords() (line 167 of core/modules/field/src/FieldStorageConfigStorage.php).
Drupal\Core\Plugin\DefaultPluginManager->getDefinition() (Line: 252)
Drupal\Core\Field\FieldTypePluginManager->getPluginClass() (Line: 163)
Drupal\field\FieldStorageConfigStorage->mapFromStorageRecords() (Line: 168)
Drupal\Core\Config\Entity\ConfigEntityStorage->doLoadMultiple() (Line: 313)
Drupal\Core\Entity\EntityStorageBase->loadMultiple() (Line: 538)
Drupal\Core\Entity\EntityBase::loadMultiple() (Line: 186)
Drupal\field\Hook\FieldHooks->entityFieldStorageInfo() (Line: 597)
Drupal\Core\Entity\EntityFieldManager->Drupal\Core\Entity\{closure}() (Line: 357)
Drupal\Core\Extension\ModuleHandler->invokeAllWith() (Line: 594)
Drupal\Core\Entity\EntityFieldManager->buildFieldStorageDefinitions() (Line: 471)
Drupal\Core\Entity\EntityFieldManager->getFieldStorageDefinitions() (Line: 302)
Drupal\field\Entity\FieldConfig->getFieldStorageDefinition() (Line: 1216)
Drupal\Core\Entity\Sql\SqlContentEntityStorage->loadFromDedicatedTables() (Line: 503)
Drupal\Core\Entity\Sql\SqlContentEntityStorage->mapFromStorageRecords() (Line: 428)
Drupal\Core\Entity\Sql\SqlContentEntityStorage->getFromStorage() (Line: 394)
Drupal\Core\Entity\Sql\SqlContentEntityStorage->doLoadMultiple() (Line: 313)
Drupal\Core\Entity\EntityStorageBase->loadMultiple() (Line: 183)
Drupal\Core\Entity\EntityRepository->getCanonicalMultiple() (Line: 175)
Drupal\Core\Entity\EntityRepository->getCanonical() (Line: 134)
Drupal\Core\ParamConverter\EntityConverter->convert() (Line: 100)
Drupal\Core\ParamConverter\ParamConverterManager->convert() (Line: 45)
Drupal\Core\Routing\Enhancer\ParamConversionEnhancer->enhance() (Line: 244)
Drupal\Core\Routing\Router->applyRouteEnhancers() (Line: 124)
Drupal\Core\Routing\Router->matchRequest() (Line: 89)
Drupal\Core\Routing\AccessAwareRouter->matchRequest() (Line: 101)
Symfony\Component\HttpKernel\EventListener\RouterListener->onKernelRequest() (Line: 246)
Symfony\Component\EventDispatcher\EventDispatcher::Symfony\Component\EventDispatcher\{closure}() (Line: 206)
Symfony\Component\EventDispatcher\EventDispatcher->callListeners() (Line: 56)
Symfony\Component\EventDispatcher\EventDispatcher->dispatch() (Line: 159)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 32)
Drupal\big_pipe\StackMiddleware\ContentLength->handle() (Line: 116)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 90)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 53)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 715)
Drupal\Core\DrupalKernel->handle() (Line: 19)

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes