Multiline TextInput backgroundColor does not fully cover surface

### Current behaviour
Multiline TextInput background color does not cover all the surface on iOS if background color have opacity.

### Expected behaviour
Multiline TextInput background color should cover all the surface on iOS.

### How to reproduce?
https://snack.expo.dev/@konstantin_bonn/textinput

### Preview

### What have you tried so far?
Try to apply contentStyle with the same color, but it just got worse.
Works fine if comment background in this workaround for iOS

```
{!isAndroid && multiline && !!label && !disabled && (
// Workaround for: https://github.com/callstack/react-native-paper/issues/2799
// Patch for a multiline TextInput with fixed height, which allow to avoid covering input label with its value.

)}
```

### Your Environment

| software | version
| --------------------- | -------
| ios | 17.2
| react-native | "0.73.6"
| react-native-paper | "^5.12.3"
| node | v20.5.0
| yarn | 1.22.19

从链接的 Expo Snack 复现开始，检查 iOS 上 multiline TextInput 的渲染，包括所示的 patch-container workaround 及其对 backgroundColor 的处理。将受影响的半透明背景情况与预期完全覆盖的表面进行比较，然后使用该复现验证 iOS 上的行为。

由索引模型根据 Issue 内容生成。