Move EE differences for `app/assets/javascripts/notes/mixins/resolvable.js`

The file app/assets/javascripts/notes/mixins/resolvable.js has differences between CE and EE.

Diferences

diff --git a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/notes/mixins/resolvable.js b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/notes/mixins/resolvable.js
index 8edf3d088bb..2329727bca2 100644
--- a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/notes/mixins/resolvable.js
+++ b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/notes/mixins/resolvable.js
@@ -31,6 +31,10 @@ export default {
   },
   methods: {
     resolveHandler(resolvedState = false) {
+      if (this.note && this.note.isDraft) {
+        return this.$emit('toggleResolveStatus');
+      }
+
       this.isResolving = true;
       const isResolved = this.discussionResolved || resolvedState;
       const discussion = this.resolveAsThread;

What needs to be done

1. Create an EE mixin and move the copy the EE version of this method there
2. Remove the if from the CE version
3. In the components where it's being imported, use ee_else_ce to import this file.