[skip ci] use refs

app/assets/javascripts/boards/components/board_sidebar.js

@@ -64,7 +64,7 @@ require('./sidebar/remove_issue');
       },
       assignSelf () {
         // Notify gl dropdown that we are now assigning to current user
-        this.$el.querySelector('.block.assignee').dispatchEvent(new Event('assignYourself'));
+        this.$refs.assigneeBlock.dispatchEvent(new Event('assignYourself'));
 
         this.addUser(this.currentUser.id);
         this.saveUsers();

app/views/projects/boards/components/sidebar/_assignee.html.haml

-.block.assignee
+.block.assignee{ ref: "assigneeBlock" }
   %template{ "v-if" => "issue.assignees"}
     %assignee-title{ ":number-of-assignees" => "issue.selectedAssigneeIds.length",
       ":loading" => "loadingAssignees",