Undefined index notice on empty exposed filter text inputs in views

We never check if there is an input index for an exposed filter before we try to fetch it from the array of inputs in FilterPluginBase::acceptExposedInput which can causes notices for empty inputs:
$value = $input[$this->options['expose']['identifier']];

Further down in FilterPluginBase::acceptExposedInput we check if the $value variable is set. But at this point, we've already received a notice.

if (isset($value)) {
  $this->value = $value;
  if (empty($this->alwaysMultiple) && empty($this->options['expose']['multiple']) && !is_array($value)) {
    $this->value = [$value];
  }
}

Stack trace:

Notice: Undefined index: filename in Drupal\views\Plugin\views\filter\FilterPluginBase->acceptExposedInput() (line 1385 of core/modules/views/src/Plugin/views/filter/FilterPluginBase.php).
Drupal\views\Plugin\views\filter\FilterPluginBase->acceptExposedInput(Array) (Line: 1352)
Drupal\views\ViewExecutable->_build('filter') (Line: 1248)
Drupal\views\ViewExecutable->build(NULL) (Line: 1377)
Drupal\views\ViewExecutable->execute(NULL) (Line: 1440)
Drupal\views\ViewExecutable->render() (Line: 33)
Drupal\entity_browser\Plugin\views\display\EntityBrowser->execute() (Line: 1616)
Drupal\views\ViewExecutable->executeDisplay('entity_browser_1') (Line: 118)
Drupal\entity_browser\Plugin\EntityBrowser\Widget\View->getForm(Array, Object, Array) (Line: 127)
Drupal\entity_browser\Form\EntityBrowserForm->buildForm(Array, Object)
call_user_func_array(Array, Array) (Line: 514)
Drupal\Core\Form\FormBuilder->retrieveForm('entity_browser_browse_files_modal_form', Object) (Line: 271)
Drupal\Core\Form\FormBuilder->buildForm('entity_browser_browse_files_modal_form', Object) (Line: 74)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 574)
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}()
call_user_func_array(Object, Array) (Line: 144)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
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: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 656)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)