missing nodes freeze the frontend

### 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 loading a workflow that has nodes not installed, then I can't close the tab, and has to erase the data of the frontend to be able to keep working,

### Steps to Reproduce

1. open any workflow with nodes not installed
2.
3.

### How is this affecting you?

Crashes ComfyUI completely

### ComfyUI Frontend Version

1.34.9

### Browser

Firefox

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-7690-missing-nodes-freeze-the-frontend-2d06d73d365081e4b310f3eac3e0ce3b) by [Unito](https://www.unito.io)