Add recent suggestions for iterations in group/project issues list

What does this MR do and why?

This MR adds recent suggestions for iterations in the group/project issues list, behind feature flag vue_issues_list. Recent suggestions exists for all the other tokens—we just forgot to add them to iterations too

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. Visit any group or project issue page such as 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.