[DevTask] Output widget in the frontend has a widget prop

Note: currently output node in the frontend also has a widget prop but it is for Primitive node only: https://github.com/Comfy-Org/ComfyUI_frontend/pull/2728

- [ ] Remove workaround: Comfy-Org/litegraph.js#735

_Originally posted by @huchenlei in https://github.com/Comfy-Org/litegraph.js/issues/732#issuecomment-2710796369_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4725-DevTask-Output-widget-in-the-frontend-has-a-widget-prop-2476d73d365081d4ab92f59ed3757420) by [Unito](https://www.unito.io)