Subgraphs don't support dragging float values out of input boxes reliably

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [x] I have searched existing issues to make sure this isn't a duplicate
- [x] I have tested with all custom nodes disabled ([see how](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled))

### What happened?

When I drag a float input out of a node with a float input box built in, then put that node in the subgraph, much of the time it will bug out when you reload the workflow. Not every time, but often.

### Steps to Reproduce

1. Add resize to megapixels node
2. Drag out input value to a float input
3. Add megapixel node to subgraph
4. Save/Load workflow or refresh
5. Randomly see "nearest neighbour" or NaN or null or even just random letters.

### How is this affecting you?

Workflow won't execute

### ComfyUI Frontend Version

1.32.9

### Browser

Chrome/Chromium

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-7138-Subgraphs-don-t-support-dragging-float-values-out-of-input-boxes-reliably-2be6d73d3650817b8723f8b522a34591) by [Unito](https://www.unito.io)

Start by reproducing the issue with the resize to megapixels node and a float input, with custom nodes disabled. Trace how subgraphs save and reload workflows, focusing on the dragged value that becomes nearest neighbour, NaN, null, or random text. Done means the float value remains correct after reload or refresh and the workflow executes.

Written by the indexing model from the issue text.