Add webSocketTroubleshooting  into product.json

Need to provide the right reference for `webSocketTroubleshooting` into product.json.
The reference in the upstream: https://github.com/eclipse/che-dashboard/blob/master/src/assets/branding/product.json#L34
The file where the right URL should be filled in https://github.com/redhat-developer/codeready-workspaces/blob/crw-2.4-rhel-8/assembly/branding/product.json.template#L30

In the upstream docs that article appeared in https://github.com/eclipse/che-docs/pull/1445