Worker setup not working on DigitalOcean

It looks like worker content CDN page can have a blank stack name in domains on DigitalOcean, but not initially. user reported workers being unable to be re-enabled after being disabled, and domain name was missing prefix which should be stack name IIRC.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/HUBS-1045)

Start by reproducing worker setup and re-enabling on DigitalOcean, then trace how the worker content CDN domain and stack name are generated. Done means workers can be re-enabled and the domain includes the expected stack-name prefix instead of being blank or missing it.

Written by the indexing model from the issue text.