Sort milestones correctly on project/issues list refactor

What does this MR do and why?

This MR:

• Sorts filtered search milestones using GraphQL
• Removes duplicate token sorting
• Updates inject from object to array
• Reorganises imports

Behind feature flag vue_issues_list defaulted to off #322755 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. In rails console enable the feature flag

   Feature.enable(:vue_issues_list)

2. Go to a group/project issues page, e.g. http://127.0.0.1:3000/h5bp/html5-boilerplate/-/issues/
3. Test the MR

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.