Fix `req.action` is `undefined` can not read `includes`

When using the mock-client, it looks like other WS events are also catched and they may not contain the `action` property. This leads to the following error:
<img width="1065" alt="Capture d’écran 2023-03-06 à 23 07 28" src="https://user-images.githubusercontent.com/39373170/223724522-fa93f1c3-b003-402c-894f-3e1c49173057.png">
