Move EE differences for `app/assets/javascripts/boards/components/board_new_issue.vue`

The file app/assets/javascripts/boards/components/board_new_issue.vue has differences between CE and EE.

Diferences

diff --git a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/boards/components/board_new_issue.vue b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/boards/components/board_new_issue.vue
index 28d96dab605..67d2d287423 100644
--- a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/boards/components/board_new_issue.vue
+++ b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/boards/components/board_new_issue.vue
@@ -51,11 +51,14 @@ export default {
 
       const labels = this.list.label ? [this.list.label] : [];
       const assignees = this.list.assignee ? [this.list.assignee] : [];
+      const milestone = this.list.milestone ? this.list.milestone : null;
+
       const issue = new ListIssue({
         title: this.title,
         labels,
         subscribed: true,
         assignees,
+        milestone,
         project_id: this.selectedProject.id,
       });

What needs to be done

1. Use ifEE together with this.list.milestone

https://leipert-projects.gitlab.io/is-gitlab-pretty-yet/diff/?search=app%2Fassets%2Fjavascripts%2Fboards%2Fcomponents%2Fboard_new_issue.vue