[Bug]:forgeui： Expecting value: line 1 column 1

### Checklist

- [ ] The issue exists after disabling all extensions
- [X] The issue exists on a clean installation of webui
- [X] The issue is caused by an extension, but I believe it is caused by a bug in the webui
- [ ] The issue exists in the current version of the webui
- [X] The issue has not been reported before recently
- [ ] The issue has been reported before but has not been fixed yet

### What happened?

After an update, the program became unusable. Reinstalling it didn't help either.

### Steps to reproduce the problem

1. In order to use laydiffusion, I updated the program once in the built-in extension installation.
2. The program is not working, I re-downloaded the installation package, but it still doesn't work.

### What should have happened?

1

### What browsers do you use to access the UI ?

Google Chrome

### Sysinfo

1

### Console logs

```Shell
Python 3.10.6 (tags/v3.10.6:9c7b4bd, Aug 1 2022, 21:53:49) [MSC v.1932 64 bit (AMD64)]
Version: f0.0.17v1.8.0rc-latest-276-g29be1da7
Commit hash: 29be1da7cf2b5dccfc70fbdd33eb35c56a31ffb7
Launching Web UI with arguments:
Total VRAM 16380 MB, total RAM 16253 MB
Set vram state to: NORMAL_VRAM
Device: cuda:0 NVIDIA GeForce RTX 4060 Ti : native
Hint: your device supports --pin-shared-memory for potential speed improvements.
Hint: your device supports --cuda-malloc for potential speed improvements.
Hint: your device supports --cuda-stream for potential speed improvements.
VAE dtype: torch.bfloat16
CUDA Stream Activated: False
Using pytorch cross attention
ControlNet preprocessor location: E:\stable-diffusion-webui-forge\webui\models\ControlNetPreprocessor
Loading weights [15012c538f] from E:\stable-diffusion-webui-forge\webui\models\Stable-diffusion\realisticVisionV51_v51VAE.safetensors
2024-03-18 19:27:15,984 - ControlNet - INFO - ControlNet UI callback registered.
Running on local URL: http://127.0.0.1:7860

To create a public link, set `share=True` in `launch()`.
model_type EPS
UNet ADM Dimension 0
Startup time: 16.6s (prepare environment: 3.8s, import torch: 4.7s, import gradio: 1.5s, setup paths: 1.1s, initialize shared: 0.2s, other imports: 0.9s, load scripts: 3.0s, create ui: 0.7s, gradio launch: 0.6s).
Using pytorch attention in VAE
Working with z of shape (1, 4, 32, 32) = 4096 dimensions.
Using pytorch attention in VAE
extra {'cond_stage_model.clip_l.logit_scale', 'cond_stage_model.clip_l.text_projection'}
loaded straight to GPU
To load target model BaseModel
Begin to load 1 model
[Memory Management] Current Free GPU Memory (MB) = 13569.03662109375
[Memory Management] Model Memory (MB) = 0.00762939453125
[Memory Management] Minimal Inference Memory (MB) = 1024.0
[Memory Management] Estimated Remaining GPU Memory (MB) = 12545.028991699219
Moving model(s) has taken 0.03 seconds
To load target model SD1ClipModel
Begin to load 1 model
[Memory Management] Current Free GPU Memory (MB) = 13569.02783203125
[Memory Management] Model Memory (MB) = 454.2076225280762
[Memory Management] Minimal Inference Memory (MB) = 1024.0
[Memory Management] Estimated Remaining GPU Memory (MB) = 12090.820209503174
Moving model(s) has taken 0.17 seconds
Model loaded in 6.0s (load weights from disk: 0.7s, forge instantiate config: 0.2s, forge load real models: 4.5s, calculate empty prompt: 0.6s).
```

### Additional information

_No response_

Start by reproducing the failure through the built-in extension installation for laydiffusion and inspect the console logs around the “Expecting value” error. Compare the clean installation and updated installation states; done means the web UI starts and remains usable after the extension update.

Written by the indexing model from the issue text.