Resolve "Add path and reference fields to GraphQL Feature Flag Type"

What does this MR do and why?

path and reference are needed for feature flags within work items to be at parity with issues.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Visit Graphiql http://127.0.0.1:3000/-/graphql-explorer
2. Enter a query for a work item with a feature flag linked to it, for example:

query namespaceWorkItem($fullPath: ID!, $iid: String!) {
  workspace: namespace(fullPath: $fullPath) {
    id
    workItem(iid: $iid) {
      id
      widgets {
        ... on WorkItemWidgetDevelopment {
          type
          featureFlags {
            nodes {
              id
              path
              reference
            }
          }
        }
      }
    }
  }
}

Related to #481901 (closed)