fix: when find already_loaded model, remove loaded by array index
diff --git a/modules/sd_models.py b/modules/sd_models.py
index b35aecbcaae..ba5bbea4fec 100644
--- a/modules/sd_models.py
+++ b/modules/sd_models.py
@@ -796,7 +796,7 @@ def reuse_model_from_already_loaded(sd_model, checkpoint_info, timer):
 
         if len(model_data.loaded_sd_models) > shared.opts.sd_checkpoints_limit > 0:
             print(f"Unloading model {len(model_data.loaded_sd_models)} over the limit of {shared.opts.sd_checkpoints_limit}: {loaded_model.sd_checkpoint_info.title}")
-            model_data.loaded_sd_models.pop()
+            del model_data.loaded_sd_models[i]
             send_model_to_trash(loaded_model)
             timer.record("send model to trash")
 

## Description

when model already loaded, the model cache need to remove is not last, so use array index instead of pop last

## Screenshots/videos:


## Checklist:

- [x] I have read [contributing wiki page](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Contributing)
- [x] I have performed a self-review of my own code
- [x] My code follows the [style guidelines](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Contributing#code-style)
- [x] My code passes [tests](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Tests)
