Disantangle a generation of servicex tokens for coffea-casa (when servicex is disabled)

[oshadura]

Server spawn is failing because of missing servicex-token secret as soon as servicex is disabled at coffea-casa AF (to reproduce the issue disable servicex in flux kustomisations for OD instance https://coffea-opendata.casa/)

[E 2022-07-26 09:58:35.173 JupyterHub pages:380] Previous spawn for [email protected] failed: (404)
    Reason: error
    HTTP response headers: HTTPHeaderDict({'Audit-Id': '4a10e62a-2de0-4ad8-a046-deca0ee7076b', 'Cache-Control': 'no-cache, private', 'Content-Type': 'application/json', 'X-Kubernetes-Pf-Flowschema-Uid': '39f91a46-9eaa-475f-b6cb-d8b931f4e9a3', 'X-Kubernetes-Pf-Prioritylevel-Uid': '6a64e91d-1d6a-4ee2-afe9-df528ed6680d', 'Date': 'Tue, 26 Jul 2022 09:58:35 GMT', 'Content-Length': '202'})
    HTTP response body: {"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"secrets \"servicex-token\" not found","reason":"NotFound","details":{"name":"servicex-token","kind":"secrets"},"code":404}