feat(server): improve validation of albums (#2188)

* feat(server): improve validation of albums

* regenerate openapi + fix downloadArchive for web

mobile/openapi/test/create_album_share_link_dto_test.dart

@@ -21,7 +21,7 @@ void main() {
       // TODO
     });
 
-    // String expiresAt
+    // DateTime expiresAt
     test('to test the property `expiresAt`', () async {
       // TODO
     });