[Bug]: 同一个FragmentActivity，2个包含webview flutter 页面的Fragment，第二个打开，客户端崩溃

### 请描述遇到的问题，以及您所期望的正确的结果

同一个FragmentActivity，2个包含webview的Fragment，使用example中 _open flutter fragment page_ 把里面第二个和三个fragment都改成包含webview的Flutter页面（url为 platformview/simplewebview ），打开第二个fragment之后，再打开第三个fragment，客户端崩溃，错误日志如下：
```
Process: com.idlefish.flutterboost.example, PID: 31135
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.view.ViewGroup.addViewInner(ViewGroup.java:5109)
at android.view.ViewGroup.addView(ViewGroup.java:4940)
at android.view.ViewGroup.addView(ViewGroup.java:4880)
at android.view.ViewGroup.addView(ViewGroup.java:4853)
at io.flutter.plugin.platform.PlatformViewsController.attachToView(PlatformViewsController.java:798)
at io.flutter.embedding.android.FlutterView.attachToFlutterEngine(FlutterView.java:1215)
at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onCreateView(FlutterActivityAndFragmentDelegate.java:338)
at io.flutter.embedding.android.FlutterFragment.onCreateView(FlutterFragment.java:806)
at com.idlefish.flutterboost.containers.FlutterBoostFragment.onCreateView(FlutterBoostFragment.java:102)
at com.idlefish.flutterboost.example.tab.FriendFlutterFragment2.onCreateView(FriendFlutterFragment2.java:19)
at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:434)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)
at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150)
at android.os.Handler.handleCallback(Handler.java:907)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:216)
at android.app.ActivityThread.main(ActivityThread.java:7779)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:990)
```

### 请说明如何操作会遇到上述问题

同一个FragmentActivity，2个包含webview的Fragment，使用example中 _open flutter fragment page_ 把里面第二个和三个fragment都改成包含webview的Flutter页面（url为 platformview/simplewebview ），打开第二个fragment之后，再打开第三个fragment，出现以上问题；
目前分析来看，是由于单引擎导致，这个有计划兼容吗？

### 在下面填入关键复现代码

使用的example 例子的 com.idlefish.flutterboost.example.tab.TabMainActivity 页面，修改代码如下：

```
private FriendFlutterFragment friendFragment;
public FriendFlutterFragment2 nativeFragment;
```

```
friendFragment = new FriendFlutterFragment
.CachedEngineFragmentBuilder(FriendFlutterFragment.class)
.url("platformview/simplewebview")
.build();

nativeFragment = new FriendFlutterFragment2
.CachedEngineFragmentBuilder(FriendFlutterFragment2.class)
.url("platformview/simplewebview")
.build();
```

### 复现的平台

Android

### Flutter SDK版本

3.7.7

### FlutterBoost版本

4.4.2

### 是否延迟初始化FlutterBoost

No

### 解决方案

Reproduce the crash from the example's TabMainActivity using two CachedEngineFragmentBuilder fragments with platformview/simplewebview. Read FlutterBoostFragment.onCreateView and the stack-traced PlatformViewsController.attachToView path; done means opening both fragments no longer raises the specified-child-already-has-a-parent exception.

Written by the indexing model from the issue text.