[Bug]: activityQueue获取currentActivity有问题

### 请描述遇到的问题，以及您所期望的正确的结果

FlutterBoost 4.3.0版本
FlutterBoost.java文件第144行currentActivity的获取有问题
FlutterBoost.java文件第357行onActivityDestroyed方法回调并非实时调用.

当一个activity通过FlutterBoost开启Flutter新的容器页面时,立刻调用自身finish()方法时,
会导致FlutterBoost.java文件第357行onActivityDestroyed方法回调有概率(很大概率)不会立刻执行
从而导致FlutterBoost.java文件第144行currentActivity获取到的栈顶的activity是一个即将被销毁的activity
从而导致了在开启的Flutter页面卡死

### 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

3.10.1

### FlutterBoost版本

4.3.0

### 是否延迟初始化FlutterBoost

No

### 解决方案

Start by reading FlutterBoost.java around line 144, where currentActivity is obtained, and line 357, where onActivityDestroyed is handled. Reproduce the reported FlutterBoost 4.3.0 sequence: open a Flutter container from an activity and immediately call finish(), using Flutter 3.10.1 on both platforms. Done means the top activity is not treated as current while it is being destroyed and the opened Flutter page does not freeze.

Written by the indexing model from the issue text.