Improve support for React v18

Hi! 👋

Firstly, thanks for your work on this project! 🙂

With React v18 children is expected to be explicitly typed

I've used [patch-package](https://github.com/ds300/patch-package) to patch `@callstack/react-theme-provider@3.0.8`

Here is the diff that solved my problem:

```diff
diff --git a/node_modules/@callstack/react-theme-provider/typings/index.d.ts b/node_modules/@callstack/react-theme-provider/typings/index.d.ts
index fd76d0e..df3cf54 100644
--- a/node_modules/@callstack/react-theme-provider/typings/index.d.ts
+++ b/node_modules/@callstack/react-theme-provider/typings/index.d.ts
@@ -8,7 +8,7 @@ type $Without = T extends any ? Pick = { [P in keyof T]?: $DeepPartial };

export type ThemingType = {
- ThemeProvider: React.ComponentType<{ theme?: Theme }>;
+ ThemeProvider: React.ComponentType<{ theme?: Theme; children: React.ReactNode }>;
withTheme: (
WrappedComponent: React.ComponentType & C
) => React.ComponentType<
```

首先定位 typings/index.d.ts 中的包类型定义，并将提供的补丁作为预期更改。验证 React v18 类型要求，并确认已发布包的类型定义允许 ThemeProvider 子元素，同时不会破坏现有的类型用法。

由索引模型根据 Issue 内容生成。