Update codeowners for Manage::Workspace team-related files

What does this MR do and why?

Add Workspace team as approvers to certain files.

Group: https://gitlab.com/groups/gitlab-org/manage/manage-workspace/backend-approvers/-/group_members?with_inherited_permissions=exclude

Files: Files are connected to the projects list API, we have discussed this here: &8164 (comment 1083572742)

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