[WT-209] fix: logger does not support string building

[JoanVicens]

The logger does not support string building, resulting into logs like this one:

{
    "hostname": "drive-server-59fbc45696-85nd2",
    "requestId": "0",
    "timestamp": "2022-11-29 09:31:05",
    "level": "error",
    "message": "[STORAGE]: ERROR applying referral for user %s: %s",
    "meta": {}
}