unable to push to image repository with unified object storage behind http proxy

Having containerized on-site gitlab (webservice ce-v17.5.2, sidekiq ce-v17.5.2) and switched "packages" to use unified object storage and set appCOnfig:packages to use an according bucket in S3.

When pushing a Helm chart to a project's registry, the Helm command reports success. Looking at the webUI (Project - Package Registry), I only see an error entry ("Helm.Temporary.Package / Error publishing · Unexpected error: Faraday::ConnectionFailed") per push.

The S3 storage is only reachable via an HTTP proxy (Squid), direct accesses to the S3 gateway IP will time out per network design. The environment variables are set up accordingly in the pods (see #479678 (closed) for a first problem report regarding this envvironment, which was worked around by updating configuration on my side and fixed by changes in code on Gitlab side later on), many other S3-based accesses work out fine.

When running tcpdump, I can see that the webservice and sidekiq pods are trying to talk to the S3 gateway directly when I push the Helm chart, so there seems to be some code not honoring the proxy settings?

@gitlab-bot label typebug @gitlab-bot label ~"category::Cloud Native Installation"