Update K8s project namespace and ServiceAccount if exist

What does this MR do?

Updates clusters/gcp/kubernetes/create_service_account_service.rb to update Kubernetes project namespaces and restricted service account, if present so that it can be re-run for the same cluster without errors

Split off from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22308 - required for group clusters to work as a whole

What are the relevant issue numbers?

#34758 (closed), #53592 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• [-] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• [-] Security reports checked/validated by reviewer