Fix Duo Workflow GraphQL API doesn't expose required fields

What does this MR do and why?

This MR fixes that the Duo Workflow GraphQL API doesn't expose required fields for namespace-level workflow execution. Required fields are listed in gitlab-org/modelops/applied-ml/code-suggestions/ai-assist!2807 (diffs).

References

Related to Agentic Chat doesn't work outside of project (G... (#550324 - closed) and feat: support namespace level workflow in agent... (gitlab-org/modelops/applied-ml/code-suggestions/ai-assist!2807 - merged)

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