Follow-up: Lazy load the product analytics query designer component

The following discussion from !105809 (merged) should be addressed:

• @jiaan started a discussion:

  praise (non-blocking): WDYT about lazy loading for the route components? This wasn't added in this MR, but I think it would make sense to lazily load the widget designer since it's a relatively large application and will likely not be used every time.

          component: () => import('./components/analytics_widget_designer.vue'),