Update workhorse_google_client feature flag definition

🐴 Context

In Improve Google Cloud Storage support (&9457 - closed), we have been working towards improving the Google Cloud Storage support.

The main change is, for workhorse assisted uploads, we will not hand an upload presigned url to workhorse. Instead, workhorse will leverage an internal client (powered by go-cloud) to upload files to the given key on object storage. This approach uses the official object storage clients which can do a lot for us out of the box (see &9457 (closed)).

This change being quite deep (all workhorse assisted uploads, including ci artifacts and package registry), we used a feature flag to gate the changes: workhorse_google_client.

The change is now ready for the rollout but we need to update a few things around the feature flag which is what this MR does.

The feature flag rollout issue is [Feature flag] workhorse_google_client rollout (#372596 - closed).

🔬 What does this MR do and why?

• Update the workhorse_google_client definition:
  • to be a gitlab_com_derisk.
  • use the current request actor.
    • The feature flag evaluation is located in a place where we don't have access to a project, user or a group. We thus, are kind of "forced" to use a request actor.

No changes on the specs side as the feature flag already exists within the codebase. This is merely a "feature flag migration".

Again, to be clear here, the production rollout has not started yet (at the time of this writing). The feature flag is fully enabled on non production environment. Hence, I think we are safe to do such "feature flag migration".

🏎 MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

✅

🌈 Screenshots or screen recordings

No changes in the UI.

⚙ How to set up and validate locally

If interested, you can follow

!96891 (merged)