feat: Never restart session containers

Failing session containers can result in restart loop until the garbage
cleaner terminates the session after 90 minutes.
Most of the failing containers do fail after restarts again and produce
unnecessary costs.

In the rare cases of one-time failures, the session can be created again
in the frontend / via the API.

backend/capellacollab/sessions/operators/k8s.py

@@ -563,7 +563,7 @@ def _create_deployment(
                             )
                         ],
                         volumes=k8s_volumes,
-                        restart_policy="Always",
+                        restart_policy="Never",
                     ),
                 ),
             ),