Media Assets (Generated) window is empty when node output is missing

### Prerequisites

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

### What happened?

Occasionally, when a node has an incorrect output, the Media Assets (Generated) window fails to load with error message "Error fetching jobs..."

```
[Jobs API] Error fetching jobs: ZodError: [
{
"code": "invalid_type",
"expected": "string",
"received": "undefined",
"path": [
"jobs",
5,
"preview_output",
"filename"
],
"message": "Required"
},
{
"code": "invalid_type",
"expected": "string",
"received": "undefined",
"path": [
"jobs",
5,
"preview_output",
"subfolder"
],
"message": "Required"
},
{
"expected": "'input' | 'output' | 'temp'",
"received": "undefined",
"code": "invalid_type",
"path": [
"jobs",
5,
"preview_output",
"type"
],
"message": "Required"
}
]

```

It fails to load a job, but then all other Generated jobs are affected and not shown anymore.
Temporary fix is to use safeParse() so if there's a job that errored, it's ignored:
```
FILE=$(grep -r "Error fetching jobs" ~/miniconda3 --include="*.js" -l 2>/dev/null | head -1)

sed -i 's/let n=vn.parse(await t.json());return{jobs:n.jobs,total:n.pagination.total,offset:r}/let _r=await t.json(),_j=(_r.jobs??[]).flatMap((j)=>{let _p=vn.shape.jobs.element.safeParse(j);if(!_p.success){console.warn("[Jobs API] Skipping invalid job:",j);return[]}return[_p.data]});return{jobs:_j,total:_r.pagination?.total??_j.length,offset:r}/' "$FILE"
```

### Steps to Reproduce

1.
2.
3.

### How is this affecting you?

Visual/UI issue only

### ComfyUI Frontend Version

1.17

### Browser

Firefox

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-9854-Media-Assets-Generated-window-is-empty-when-node-output-is-missing-3226d73d365081e68c61c27698709e6e) by [Unito](https://www.unito.io)