Draft: Add awardEmojiSummary to workItem type

What does this MR do and why?

Add awardEmojiSummary to workItem type

Summarize award emoji count and username list

How to set up and validate locally

Run a GraphQL query like the following:

{
  project(fullPath: "gitlab-org/gitlab") {
    workItems(iid: "414775") {
      nodes {
        id
        widgets {
          type
          ... on WorkItemWidgetAwardEmoji {
            summary {
              name
              count
              usernames
              awardedByCurrentUser
            }
          }
        }
      }
    }
  }
}

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #414857 (closed)