Issue #3337216 by _tarik_, alorenc, zaryab_drupal, claudiu.cristea, dd_diablo,...

Issue #3337216 by _tarik_, alorenc, zaryab_drupal, claudiu.cristea, dd_diablo, bohart: Replace PrivateMessageThread::load with dependency injection

src/Controller/AjaxController.php

@@ -20,7 +20,6 @@ use Drupal\private_message\Ajax\PrivateMessageInsertThreadCommand;
 use Drupal\private_message\Ajax\PrivateMessageMemberUsernameValidatedCommand;
 use Drupal\private_message\Ajax\PrivateMessageMembersAutocompleteResponseCommand;
 use Drupal\private_message\Ajax\PrivateMessageUpdateUnreadItemsCountCommand;
-use Drupal\private_message\Entity\PrivateMessageThread;
 use Drupal\private_message\Service\PrivateMessageBanManagerInterface;
 use Drupal\private_message\Service\PrivateMessageServiceInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -435,7 +434,7 @@ class AjaxController extends ControllerBase implements AjaxControllerInterface {
   protected function loadThread(AjaxResponse $response) {
     $thread_id = $this->requestStack->getCurrentRequest()->get('id');
     if ($thread_id) {
-      $thread = PrivateMessageThread::load($thread_id);
+      $thread = $this->entityTypeManager->getStorage('private_message_thread')->load($thread_id);
 
       if ($thread && $thread->access('view', $this->currentUser)) {
         $this->privateMessageService->updateLastCheckTime();