Revisit versioning of #create_config_to_apply in #create_workspace_agent_info_hash

MR: Pending

Description

The following discussion from !129715 (merged) should be addressed:

• @cwoolley-gitlab started a discussion: (+5 comments)

  @vtak I was reviewing this, and I had some concerns about this call to #create_config_to_apply from within #create_workspace_agent_info_hash:

  https://gitlab.com/gitlab-org/gitlab/-/blob/90e2c698b79efe102e542e76b650d33a1e565c48/ee/spec/support/shared_contexts/remote_development/remote_development_shared_contexts.rb#L257

  It seems like in order to generate completely realistic fixture data for the agent info hash, instead of hardcoding this to call the latest/current create_config_to_apply, it should be dependent upon the current config_version for the workspace, and call either create_config_to_apply or create_config_to_apply_prev1 accordingly.

  If you agree, I can make a follow-up issue to clean this up, and probably introduce the concept of the config to apply being dependent upon the current workspace version.

  But I don't want to do this yet, because I'm about to create an MR to clean up the signatures for these helper methods as part of Improve defaults for remote_development_shared_... (#409787 - closed)

Acceptance Criteria

TODO: Fill out (required)

• Call the correct version of create_config_to_apply/create_config_to_apply_prev1 based upon the current config_version for the workspace, as described above.
• Consider whether it would be better to switch to vn instead of prevn as a naming convention for older config versions (see related discussion on original linked thread).