Simplify DAP graphql API: Add detailed ui_chat_log JSON fields

What does this MR do and why?

Simplify Duo Agent Platform graphql API: Add detailed ui_chat_log JSON fields

References

Related to #535898 (closed)

How to set up and validate locally

Test http://gdk.test:3000/-/graphql-explorer

query getFlow {
  duoWorkflowWorkflows(workflowId: "gid://gitlab/Ai::DuoWorkflows::Workflow/318") {
    nodes {
      id
      latestCheckpoint {
        workflowGoal
        duoMessages {
          content
          correlationId
          role
          statusa
          timestamp
          toolInfo
        }
      }
    }
  }
}		

To test the subscription just continue your chat while running the below

subscription getFlowEvents {
  workflowEventsUpdated(workflowId: "gid://gitlab/Ai::DuoWorkflows::Workflow/318") {
    duoMessages {
      content
      timestamp
    }
    checkpoint
  }
}

MR acceptance checklist

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