Exporter tries to get workflow usage from enterprise server

[kegfru]

Exporter tries to get 'https://api.github.com/repos/OWNER/REPO/actions/workflows/WORKFLOW_ID/timing' and get 404s
Get workflow usage exists only in github.com based actions
https://docs.github.com/en/rest/actions/workflows?apiVersion=2022-11-28#get-workflow-usage
but not in Enterpise servers
https://docs.github.com/en/enterprise-server@3.7/rest/actions/workflows#get-a-workflow