feat(server) Extend PUT /album/:id/assets endpoint (#857)

* Add new query parameter to API endpoint that allows adding assets to albums which potentially contain assets that are already part of this album.

* Change API endpoint

* Generate new APIs

* Fixed test

Co-authored-by: Alex Tran <alex.tran1502@gmail.com>

mobile/openapi/lib/api_client.dart

@@ -194,6 +194,8 @@ class ApiClient {
           return value is DateTime ? value : DateTime.tryParse(value);
         case 'AddAssetsDto':
           return AddAssetsDto.fromJson(value);
+        case 'AddAssetsResponseDto':
+          return AddAssetsResponseDto.fromJson(value);
         case 'AddUsersDto':
           return AddUsersDto.fromJson(value);
         case 'AdminSignupResponseDto':