Fix psalm warnings

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

apps/dashboard/lib/Controller/DashboardController.php

@@ -152,7 +152,7 @@ class DashboardController extends Controller {
 			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
 		}
 		$currentVersion++;
-		$this->config->setUserValue($this->userId, 'dashboard', 'backgroundVersion', $currentVersion);
+		$this->config->setUserValue($this->userId, 'dashboard', 'backgroundVersion', (string)$currentVersion);
 		return new JSONResponse([
 			'type' => $type,
 			'value' => $value,

apps/dashboard/lib/Service/BackgroundService.php

@@ -141,6 +141,7 @@ class BackgroundService {
 	 */
 	public function setFileBackground($path): void {
 		$this->config->setUserValue($this->userId, 'dashboard', 'background', 'custom');
+		/** @var \OCP\Files\File $file */
 		$file = $this->userFolder->get($path);
 		$this->dashboardUserFolder->newFile('background.jpg', $file->fopen('r'));
 	}