Cancelled workflow jobs put CI in a limbo state

If you cancel a CI job while building, it starts executing `Reporting disk usage` step which waits for the bazel to release the lock.

```
Another command (pid=2692) is running. Waiting for it to complete on the server (server_pid=2702)...
```

Ref: https://github.com/cloudflare/workerd/actions/runs/13707698229/job/38336925984?pr=3594

cc @fhanau @mikea