Promoted indicator inside parent subgraph is missing on nested subgraphs.

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [ ] I have custom nodes enabled

### What happened?

Great work on fixing nested subgraphs. Thanks.
The visual indicator for promoted widgets is missing from nested subgraphs.

Additionally, subgraphs loose their promoted widgets when packed (by hitting the "Convert Selection to Subgraph") in a new subgraph and require manual re-promotion. They keep promotions if copied and pasted directly inside the new subgraph.

### Steps to Reproduce

1. Create subgraph and promote some widgets
2. Pack subgraph inside another and re-promote widgets.
3. Promote widgets from nested subgraph.
[test.nested.new.json](https://github.com/user-attachments/files/26299251/test.nested.new.json)

Or
1. Load workflow created in 1.39.19 or older.
[test.nested.json](https://github.com/user-attachments/files/26299175/test.nested.json)

### How is this affecting you?

Feature doesn't work as expected

### ComfyUI Frontend Version

1.43.7

### Browser

Firefox

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10612-Promoted-indicator-inside-parent-subgraph-is-missing-on-nested-subgraphs-3306d73d36508161ac60de9fc2f59def) by [Unito](https://www.unito.io)