download: add UseSession annotation

lib/Controller/AlbumsController.php

@@ -55,6 +55,8 @@ class AlbumsController extends ApiBase
     /**
      * @NoAdminRequired
      *
+     * @UseSession
+     *
      * Download an album as a zip file
      */
     public function download(string $name = ''): JSONResponse

lib/Controller/DownloadController.php

@@ -36,6 +36,8 @@ class DownloadController extends ApiBase
      *
      * @PublicPage
      *
+     * @UseSession
+     *
      * Request to download one or more files
      */
     public function request(): JSONResponse
@@ -55,6 +57,8 @@ class DownloadController extends ApiBase
     /**
      * Get a handle for downloading files.
      *
+     * The calling controller must have the UseSession annotation.
+     *
      * @param string $name  Name of zip file
      * @param int[]  $files
      */