Unable to display model download size correctly: Download (NaN undefined)

### Prerequisites

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

### What happened?

It is recommended to display a message or a retry button if retrieving the file size fails? For non-developers, `undefined` isn't very easy to understand.

I tried using curl to get the file size, but it's possible that redirection is causing the file information to not be retrieved correctly.

```
NOT WORK
curl -sI 'https://civitai.com/api/download/models/85426?type=Model&format=SafeTensor&size=pruned&fp=fp16' | grep -i content-length

curl -sIL 'https://civitai.com/api/download/models/85426?type=Model&format=SafeTensor&size=pruned&fp=fp16' | grep -i content-length
content-length: 2400041216
```

### Steps to Reproduce

1. download https://raw.githubusercontent.com/Comfy-Org/example_workflows/main/controlnet/pose_controlnet_2_pass.png
2. drag to ui

### How is this affecting you?

Visual/UI issue only

### ComfyUI Frontend Version

ComfyUI v0.16.4 ComfyUI_frontend v1.39.19 Discord ComfyOrg ComfyUI_desktop v0.8.18

### Browser

Chrome/Chromium

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-9696-Unable-to-display-model-download-size-correctly-Download-NaN-undefined-31f6d73d3650815a9e48e9fd8f5f3368) by [Unito](https://www.unito.io)