fix notifications service unit test for verticalPosition

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: lyubov-voloshko

frontend/src/app/services/notifications.service.spec.ts

@@ -55,6 +55,7 @@ describe('NotificationsService', () => {
 			Object({
 				duration: 2500,
 				horizontalPosition: 'left',
+				verticalPosition: 'bottom',
 			}),
 		);
 	});