Advanced Roadmaps plan do not respect project permissions while an issue is assigned from a plan

Issue Summary

When we click on the assignee field for an issue in an Advanced Roadmap plan, the drop-down will show all the users. Ideally, only the users with Assignable User permission for that issue should show up.

Steps to Reproduce

1. Create a plan with some project issues in it.
2. Pick any issue and click on the assignee column for it.
3. You will notice that those users who lack Assignable user permission will also show up in the list
4. Screen recording attached

Expected Results

User with assignable user permission should show up in the list and once assigned, re-click on the assignee field for the same issue displays the wrong user name.

Actual Results

All users are showing up

Workaround

No workaround available