[Bug]: In "Add Fallbacks" Pop-up, the model dropdown are rendered behind the pop-up

### What happened?

In "Add Fallbacks" Pop-up, the models dropdown are rendered behind the pop-up.

<img width="2336" height="1712" alt="Image" src="https://github.com/user-attachments/assets/c291d54f-c4c5-435f-8ba3-36d0e7ecda7f" />

### Relevant log output

```shell

```

### Are you a ML Ops Team?

No

### What LiteLLM version are you on ?

v1.80.5

### Twitter / LinkedIn details

@valevivaldi