Added saved reply field to GraphQL endpoint

What does this MR do and why?

Added saved reply field to users to allow users to return a single saved reply with an ID.

This will be used internally for the saved replies Vue app to allow us to retrieve a single saved reply when a user wants to edit a saved reply.

Screenshots or screen recordings

How to set up and validate locally

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.

#14328 (closed)