How to mock this library with jest? (Fails when used normally)

## Environment

Relevant versions:

```json
"react": "17.0.2",
"react-native": "0.66.0",
"react-native-pager-view": "^5.4.9",
```

## Description

Calling the `setPage` method on a viewPager `ref` causes jest to throw this error:

```
TypeError: Cannot read properties of undefined (reading 'Commands')

87 | if (viewPager.current) {
> 88 | viewPager.current.setPage(page);
| ^
89 | }
90 |
```

## Reproducible Demo

1. Create an integration test with any component using `ViewPager` and call `setPage` on it's ref. This error will throw.

从 issue 中描述的集成测试开始：使用 ViewPager 渲染一个组件，并在其 ref 上调用 setPage。调查 native ViewPager 实现周围的 Jest mock 或测试设置，以及 undefined Commands 错误。完成标准是测试可以调用 setPage 而不会抛出异常。

由索引模型根据 Issue 内容生成。