Unable to Remove Persistent Shadow from Modal Component in React Native Paper

### Current behaviour
I'm experiencing an issue with the Modal component in React Native Paper in iOS where I am unable to remove the shadow from the modal view. Despite trying various approaches to eliminate the shadow, it remains persistent. Where it's working fine on the android device without any shadow.

### Expected behaviour
The shadow around the Modal component should be removed based on the provided styles and theme configurations.

### Preview

### What have you tried so far?
Elevation to 0
Backdrop to white(To make the background colour of the modal white instead of opaque)

### Your Environment

| software | version
| --------------------- | -------
| ios | iOS 17.2

Start at the React Native Paper Modal component and reproduce the iOS behavior using the reported elevation and backdrop settings on iOS 17.2. Compare it with the working Android behavior and verify that the modal shadow can be removed through its styles and theme configuration.

Written by the indexing model from the issue text.