[Bug]: FlutterActivity重建后丢失Flutter路由

### 请描述遇到的问题，以及您所期望的正确的结果

Android12以上系统，在Flutter页面调用原生的WallpaperManager来设置壁纸，设置壁纸会引发系统重建Activity，重建后FlutterBoostActivity的内容被重置，Boost内的页面会被重置到初始页面，且路由也丢失了，点击返回期望回到原生页面也会直接崩溃

### 请说明如何操作会遇到上述问题

_No response_

### 在下面填入关键复现代码

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### 复现的平台

Both

### Flutter SDK版本

3.16.9

### FlutterBoost版本

4.6.5

### 是否延迟初始化FlutterBoost

No

### 解决方案

Start by reproducing the issue on Android 12 or later: invoke WallpaperManager from a Flutter page and observe FlutterBoostActivity recreation. Inspect the FlutterBoostActivity lifecycle and route restoration path; done means the Flutter route and page state survive recreation, and back navigation returns to the native page without crashing.

Written by the indexing model from the issue text.