🐛 Fixed sticky "Unsaved changes" modal when leaving editor

no issue
- the unsaved changes confirmation modal could re-appear after leaving the editor and re-opening the same post
- remove the `.finally` which assumed the confirm action returns a promise so that the modal is properly closed

app/components/modal-leave-editor.js

@@ -4,9 +4,8 @@ import RSVP from 'rsvp';
 export default ModalComponent.extend({
     actions: {
         confirm() {
-            this.confirm().finally(() => {
-                this.send('closeModal');
-            });
+            this.confirm();
+            this.send('closeModal');
         }
     },