Add proper NotFoundResponse if no avatar is available

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Controller/LocalController.php

@@ -47,6 +47,7 @@ use OCA\Social\Service\PostService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\FileDisplayResponse;
+use OCP\AppFramework\Http\NotFoundResponse;
 use OCP\AppFramework\Http\Response;
 use OCP\IRequest;
 
@@ -415,11 +416,12 @@ class LocalController extends Controller {
 	public function actorAvatar(string $id): Response {
 		try {
 			$actor = $this->personService->getFromId($id);
-			$avatar = $actor->getIcon();
-			$document = $this->documentService->getFromCache($avatar->getId());
-
-
-			return new FileDisplayResponse($document);
+			if ($actor->gotIcon()) {
+				$avatar = $actor->getIcon();
+				$document = $this->documentService->getFromCache($avatar->getId());
+				return new FileDisplayResponse($document);
+			}
+			return new NotFoundResponse();
 		} catch (Exception $e) {
 			return $this->fail($e);
 		}