Count() warnings for checkboxes on Messages page(node/{nid}/event/messages).

[uttkarsh-26]

Here is the full warning message:

Warning: count(): Parameter must be an array or an object that implements Countable in Drupal\Core\Render\Element\Checkboxes::processCheckboxes() (line 58 of core/lib/Drupal/Core/Render/Element/Checkboxes.php). Drupal\Core\Render\Element\Checkboxes::processCheckboxes(Array, Object, Array) call_user_func_array(Array, Array) (Line: 997) Drupal\Core\Form\FormBuilder->doBuildForm('rng_message_list', Array, Object) (Line: 1060) Drupal\Core\Form\FormBuilder->doBuildForm('rng_message_list', Array, Object) (Line: 1060) Drupal\Core\Form\FormBuilder->doBuildForm('rng_message_list', Array, Object) (Line: 561) Drupal\Core\Form\FormBuilder->processForm('rng_message_list', Array, Object) (Line: 318) Drupal\Core\Form\FormBuilder->buildForm('rng_message_list', Object) (Line: 93) Drupal\Core\Controller\FormController->getContentResult(Object, Object) call_user_func_array(Array, Array) (Line: 123) Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 582) Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124) Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97) Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151) Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68) Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57) Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47) Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99) Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78) Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47) Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52) Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23) Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 693) Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

#48