Add assertions for 'id' and 'event_name' in subscription detail response test

Author: Ostap-Zherebetskyi

api_tests/subscriptions/views/test_subscriptions_detail.py

@@ -342,3 +342,5 @@ def test_subscription_detail_patch(
         res = app.patch_json_api(url_user_global_file_updated, payload, auth=user.auth)
         assert res.status_code == 200
         assert res.json['data']['attributes']['frequency'] == 'none'
+        assert res.json['data'].get('id') is not None
+        assert res.json['data']['attributes'].get('event_name') is not None