Problem/Motivation
When trying to add css class to a block, site crashes with the following errors:
TypeError: array_merge(): Argument #1 must be of type array, string given in array_merge() (line 202 of /code/web/modules/contrib/block_class/src/Service/BlockClassHelperService.php).
#0 /code/web/modules/contrib/block_class/src/Service/BlockClassHelperService.php(202): array_merge('{"layout__wrapp...', Array)
#1 /code/web/modules/contrib/block_class/block_class.module(107): Drupal\block_class\Service\BlockClassHelperService->blockClassPreSave(Object(Drupal\block\Entity\Block))
#2 [internal function]: block_class_block_presave(Object(Drupal\block\Entity\Block))
#3 /code/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(416): call_user_func_array(Object(Closure), Array)
#4 /code/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(395): Drupal\Core\Extension\ModuleHandler->Drupal\Core\Extension\{closure}(Object(Closure), 'block_class')
#5 /code/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(415): Drupal\Core\Extension\ModuleHandler->invokeAllWith('block_presave', Object(Closure))
#6 /code/web/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php(341): Drupal\Core\Extension\ModuleHandler->invokeAll('block_presave', Array)
#7 /code/web/core/lib/Drupal/Core/Entity/EntityStorageBase.php(529): Drupal\Core\Config\Entity\ConfigEntityStorage->invokeHook('presave', Object(Drupal\block\Entity\Block))
#8 /code/web/core/lib/Drupal/Core/Entity/EntityStorageBase.php(483): Drupal\Core\Entity\EntityStorageBase->doPreSave(Object(Drupal\block\Entity\Block))
#9 /code/web/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php(257): Drupal\Core\Entity\EntityStorageBase->save(Object(Drupal\block\Entity\Block))
#10 /code/web/core/lib/Drupal/Core/Entity/EntityBase.php(354): Drupal\Core\Config\Entity\ConfigEntityStorage->save(Object(Drupal\block\Entity\Block))
#11 /code/web/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php(614): Drupal\Core\Entity\EntityBase->save()
#12 /code/web/core/lib/Drupal/Core/Entity/EntityForm.php(293): Drupal\Core\Config\Entity\ConfigEntityBase->save()
#13 /code/web/core/modules/block/src/BlockForm.php(362): Drupal\Core\Entity\EntityForm->save(Array, Object(Drupal\Core\Form\FormState))
#14 [internal function]: Drupal\block\BlockForm->save(Array, Object(Drupal\Core\Form\FormState))
#15 /code/web/core/lib/Drupal/Core/Form/FormSubmitter.php(129): call_user_func_array(Array, Array)
#16 /code/web/core/lib/Drupal/Core/Form/FormSubmitter.php(67): Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object(Drupal\Core\Form\FormState))
#17 /code/web/core/lib/Drupal/Core/Form/FormBuilder.php(597): Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object(Drupal\Core\Form\FormState))
#18 /code/web/core/lib/Drupal/Core/Form/FormBuilder.php(326): Drupal\Core\Form\FormBuilder->processForm('block_form', Array, Object(Drupal\Core\Form\FormState))
#19 /code/web/core/lib/Drupal/Core/Controller/FormController.php(73): Drupal\Core\Form\FormBuilder->buildForm(Object(Drupal\block\BlockForm), Object(Drupal\Core\Form\FormState))
#20 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch))
#21 /code/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array)
#22 /code/web/core/lib/Drupal/Core/Render/Renderer.php(638): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#23 /code/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(121): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure))
#24 /code/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array)
#25 /code/vendor/symfony/http-kernel/HttpKernel.php(181): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#26 /code/vendor/symfony/http-kernel/HttpKernel.php(76): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#27 /code/web/core/lib/Drupal/Core/StackMiddleware/Session.php(53): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#28 /code/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#29 /code/web/core/lib/Drupal/Core/StackMiddleware/ContentLength.php(28): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#30 /code/web/core/modules/big_pipe/src/StackMiddleware/ContentLength.php(32): Drupal\Core\StackMiddleware\ContentLength->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#31 /code/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#32 /code/web/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#33 /code/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#34 /code/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#35 /code/web/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php(36): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#36 /code/web/core/lib/Drupal/Core/StackMiddleware/StackedHttpKernel.php(51): Drupal\Core\StackMiddleware\AjaxPageState->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#37 /code/web/core/lib/Drupal/Core/DrupalKernel.php(741): Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#38 /code/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#39 {main}