调用谷歌gemini image api最新模型 gemini-2.5-flash-image-preview时出错

### Custom Node Testing

- [ ] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

修改谷歌最新模型api的节点

### Actual Behavior

跑完节点乱码，且有时候不返回结果，或者结果是原图也扣积分

### Steps to Reproduce

跟完节点就乱码了，有时候不返回结果，或者返回和参考图一模一样的结果也扣积分

### Debug Logs

```powershell
Prompt executed in 14.07 seconds
got prompt
Prompt executed in 12.20 seconds
got prompt
Prompt executed in 2.55 seconds
got prompt
Prompt executed in 1.60 seconds
终端日志没出错
```

### Other

_No response_