MvxFormsPagePresenter.CloseAllModals throwing IllegalArgumentException
## 🐛 Bug Report

I see this crash on a regular basis in my AppCenter logs from end users:
```

JniEnvironment+InstanceMethods.CallBooleanMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args)
JniPeerMembers+JniInstanceMethods.InvokeVirtualBooleanMethod (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters)
FragmentManager.ExecutePendingTransactions ()
FragmentManagerExtensions.ExecutePendingTransactionsEx (AndroidX.Fragment.App.FragmentManager fragmentManager)
NavigationPageRenderer.Dispose (System.Boolean disposing)
IJavaPeerable.Disposed ()
JniRuntime+JniValueManager.DisposePeer (Java.Interop.IJavaPeerable value)
Object.Dispose ()
Platform+ModalContainer.Dispose (System.Boolean disposing)
IJavaPeerable.Disposed ()
JniRuntime+JniValueManager.DisposePeer (Java.Interop.IJavaPeerable value)
Object.Dispose ()
INavigation.PopModalAsync (System.Boolean animated)
NavigationProxy.OnPopModal (System.Boolean animated)
Application+NavigationImpl.<>n__0 (System.Boolean animated)
Application+NavigationImpl.OnPopModal (System.Boolean animated)
MvxFormsPagePresenter.CloseAllModals (System.Boolean animate)
MvxFormsPagePresenter.CloseAndCreatePage (System.Type view, MvvmCross.ViewModels.MvxViewModelRequest request, MvvmCross.Forms.Presenters.Attributes.MvxPagePresentationAttribute attribute, System.Boolean closeModal, System.Boolean closePlatformViews, System.Boolean showPlatformViews)
MvxFormsPagePresenter.ShowContentPage (System.Type view, MvvmCross.Forms.Presenters.Attributes.MvxContentPagePresentationAttribute attribute, MvvmCross.ViewModels.MvxViewModelRequest request)
MvxMainThreadAsyncDispatcher+<>c__DisplayClass1_0.<ExecuteOnMainThreadAsync>b__0 ()
AsyncMethodBuilderCore+<>c.<ThrowAsync>b__7_0 (System.Object state)
SyncContext+<>c__DisplayClass2_0.<Post>b__0 ()
Thread+RunnableImplementor.Run ()
IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this)
(wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.54(intptr,intptr)
java.lang.IllegalArgumentException: No view found for id 0x30 (unknown) for fragment FragmentContainer{6f04bd1} (ec319f9c-446f-4ad0-9c0e-6d1d631a1d55) id=0x30}
androidx.fragment.app.FragmentStateManager.createView FragmentStateManager.java:315
androidx.fragment.app.FragmentManager.moveToState FragmentManager.java:1199
androidx.fragment.app.FragmentManager.moveToState FragmentManager.java:1368
androidx.fragment.app.FragmentManager.moveFragmentToExpectedState FragmentManager.java:1446
androidx.fragment.app.FragmentManager.moveToState FragmentManager.java:1509
androidx.fragment.app.BackStackRecord.executeOps BackStackRecord.java:447
androidx.fragment.app.FragmentManager.executeOps FragmentManager.java:2181
androidx.fragment.app.FragmentManager.executeOpsTogether FragmentManager.java:2004
androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute FragmentManager.java:1959
androidx.fragment.app.FragmentManager.execPendingActions FragmentManager.java:1861
androidx.fragment.app.FragmentManager.executePendingTransactions FragmentManager.java:489
crc643f46942d9dd1fff9.GenericMenuClickListener.n_onMenuItemClick(Native Method)
crc643f46942d9dd1fff9.GenericMenuClickListener.onMenuItemClick GenericMenuClickListener.java:30
androidx.appcompat.view.menu.MenuItemImpl.invoke MenuItemImpl.java:154
androidx.appcompat.view.menu.MenuBuilder.performItemAction MenuBuilder.java:985
androidx.appcompat.view.menu.MenuBuilder.performItemAction MenuBuilder.java:975
androidx.appcompat.widget.ActionMenuView.invokeItem ActionMenuView.java:623
androidx.appcompat.view.menu.ActionMenuItemView.onClick ActionMenuItemView.java:151
android.view.View.performClick View.java:8160
android.widget.TextView.performClick TextView.java:16222
android.view.View.performClickInternal View.java:8137
android.view.View.access$3700 View.java:888
android.view.View$PerformClick.run View.java:30236
android.os.Handler.handleCallback Handler.java:938
android.os.Handler.dispatchMessage Handler.java:99
android.os.Looper.loop Looper.java:246
android.app.ActivityThread.main ActivityThread.java:8595
java.lang.reflect.Method.invoke(Native Method)
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run RuntimeInit.java:602
com.android.internal.os.ZygoteInit.main ZygoteInit.java:1130
```

Any help would be appreciated, as I have no clue why this would be happening. Not sure if this bug has already been submitted, otherwise this can be linked & closed.

### Expected behavior
Should not crash.

### Reproduction steps
I am assuming this happens when I close a Modal-page that uses the `[MvxModalPresentation]` attribute.

### Configuration

**Version:** 7.1.2

**Platform:** 
- [ ] :iphone: iOS
- [x] :robot: Android
- [ ] :checkered_flag: WPF
- [ ] :earth_americas: UWP
- [ ] :apple: MacOS
- [ ] :tv: tvOS
- [x] :monkey: Xamarin.Forms
