as a workaround you can use the same websocket used by the sisense UI or get data from mongodb. If your app is able to run kubectl on the mongodb container, you can get session data as follows:
kubectl -n <sisenseNamespace> exec -it <yourNamespace>-mongodb-0 -c mongodb -- mongo prismWebDB --quiet --eval 'db.getCollection("socket-sessions").find({"registrationDetails.headers.authentication.isAuthenticated": true}, {_id: 0, "registrationDetails.user.userName": 1, "registrationDetails.user.baseRoleName": 1, "registrationDetails.user.tenant.name": 1}).toArray();'
As an alternative, you can enable readuser to access mongodb and access from your app, then run the same query I provided in the previous example. Many other details are available; I just selected the ones I needed, but you can add more or simply get all and handle the useful one in your app