Adapt the current Helm's OCI code to use the upstream version

[antgamdia]

After the discussion held in #4154 (comment), we agree that we should migrate to Helm 3.8.X, but their current interface to consume the OCI registry client is not enough for us.

This issue is to track the two required steps:

• Make a PR in the Helm repository (related issue: Improve OCI registry client configuration options for devs helm/helm#10623)
• Adapt our code to the new Helm 3.8.X release.
• Wait until they release a version including our PR
• Re-apply the changes in the linked PR manually with the now refactored code.

[antgamdia]

Helm folks have suggested some minor changes (mostly just targeting another ongoing PR). Ideally, it would be ready for the 3.8.1 release due on March 9th, so I'll perform those changes next week.