[Bug]: Unload SD checkpoint to RAM not working

[dmi]

Checklist

• [X] The issue exists after disabling all extensions
• [X] The issue exists on a clean installation of webui
• [ ] The issue is caused by an extension, but I believe it is caused by a bug in the webui
• [X] 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?

"Settings/Actions/Unload SD checkpoint to RAM" cause no effect. Complemmetar API call sdapi/v1/unload-checkpoint not working too.

In the original A1111 this works and free VRAM.

Steps to reproduce the problem

1. Generate some image
2. note VRAM used by running nvidia-smi
3. Go to Settings/Actions, press "Unload SD checkpoint to RAM"
4. Rerun nvidia-smi: VRAM still filled.

What should have happened?

Expected: VRAM mostly cleared after "Unload..."

What browsers do you use to access the UI ?

Apple Safari

Sysinfo

sysinfo-2024-05-14-11-01.json

Console logs

Begin to load 1 model
[Memory Management] Current Free GPU Memory (MB) =  14367.57470703125
[Memory Management] Model Memory (MB) =  159.55708122253418
[Memory Management] Minimal Inference Memory (MB) =  1024.0
[Memory Management] Estimated Remaining GPU Memory (MB) =  13184.017625808716
Moving model(s) has taken 0.03 seconds
Total progress: 100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 20/20 [00:05<00:00,  3.63it/s]
Total progress: 100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 20/20 [00:05<00:00,  3.97it/s]

Additional information

No response