some bug with Modal and Portal

### Current behaviour
The modal may cause a quick flash; setting dismissable to false does not resolve this issue.
Additionally, the modal can result in an unsmooth exit when used with react-native-maps.
Moreover, when attempting to embed a Portal into a List on iOS, the entire component sometimes becomes hidden, although this issue does not occur on Android.
### Expected behaviour

### How to reproduce?

### Preview

### What have you tried so far?

### Your Environment

| software | version
| --------------------- | -------
| ios | x
| android | x
| react-native | x.x.x
| react-native-paper | x.x.x
| node | x.x.x
| npm or yarn | x.x.x
| expo sdk | x.x.x

首先在 iOS 上复现所报告的 Modal 和 Portal 行为，包括快速闪现、使用 react-native-maps 时不流畅的退出，以及 List 内隐藏的 Portal。将其与 Android 上的行为进行比较，并利用所报告的环境详细信息缩小原因范围；当这些 iOS 场景运行流畅且 Portal 保持可见时，即表示完成。

由索引模型根据 Issue 内容生成。