Take Recorder crashes if actor with animation despawns during recording

Skeletal animations are finalized at the end of recording, and expect the actor to still be around, but actors can despawn during recording leading to a crash.

1. Create a sequence with a spawnable mannequin
2. Animate the spawn track so the mannequin spawns a few frames in to the sequence.
3. Add an animation to the mannequin
4. Add a Level Sequence source to take recorder, and add the sequence from step 1 to the list of sequences to trigger
5. Add a source for nearby spawned actors
6. PIE
7. Record a take
8. Wait for the skeletal mesh actor source to become Actor (none) and stop recording

RESULT

The editor crashes

Fatal error!

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x000000000000050c

0x00007ffb5958de16 UE4Editor-CoreUObject.dll!FWeakObjectPtr::Get() [D:\_Release-4.26\Engine\Source\Runtime\CoreUObject\Private\UObject\WeakObjectPtr.cpp:81]
0x00007ffb4be307a0 UE4Editor-SequenceRecorder.dll!FAnimationRecorder::ProcessRecordedTimes() [D:\_Release-4.26\Engine\Source\Editor\SequenceRecorder\Private\AnimationRecorder.cpp:505]
0x00007ffb326f8a07 UE4Editor-TakeTrackRecorders.dll!UMovieSceneAnimationTrackRecorder::ProcessRecordedTimes() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakeTrackRecorders\Private\MovieSceneAnimationTrackRecorder.cpp:318]
0x00007ffb32635962 UE4Editor-TakeRecorderSources.dll!UTakeRecorderActorSource::PostProcessTrackRecorders() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakeRecorderSources\Private\TakeRecorderActorSource.cpp:854]
0x00007ffb32635f3c UE4Editor-TakeRecorderSources.dll!UTakeRecorderActorSource::PostRecording() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakeRecorderSources\Private\TakeRecorderActorSource.cpp:742]
0x00007ffb32797d28 UE4Editor-TakesCore.dll!UTakeRecorderSources::StopRecording() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakesCore\Private\TakeRecorderSources.cpp:562]
0x00007ffb31ac4965 UE4Editor-TakeRecorder.dll!UTakeRecorder::Stop() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakeRecorder\Private\Recorder\TakeRecorder.cpp:880]
0x00007ffb31a55793 UE4Editor-TakeRecorder.dll!STakeRecorderNotification::ButtonClicked() [D:\_Release-4.26\Engine\Plugins\VirtualProduction\Takes\Source\TakeRecorder\Private\Recorder\TakeRecorder.cpp:266]
0x00007ffb31a7c7ee UE4Editor-TakeRecorder.dll!TBaseSPMethodDelegateInstance<0,STakeRecorderNotification,0,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() [D:\_Release-4.26\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:290]
0x00007ffb57fbc2ae UE4Editor-Slate.dll!SButton::ExecuteOnClick() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:385]
0x00007ffb57fd47b2 UE4Editor-Slate.dll!SButton::OnMouseButtonUp() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:304]
0x00007ffb57e147be UE4Editor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_cc5aea9e7377b04ce85c30c65ec3889b> >() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:378]
0x00007ffb57e986b4 UE4Editor-Slate.dll!FSlateApplication::RoutePointerUpEvent() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4815]
0x00007ffb57e80a37 UE4Editor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5356]
0x00007ffb57e73d72 UE4Editor-Slate.dll!FSlateApplication::OnMouseUp() [D:\_Release-4.26\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5321]
0x00007ffba379bdb7 UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [D:\_Release-4.26\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2178]
0x00007ffba3789227 UE4Editor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [D:\_Release-4.26\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2642]
0x00007ffba379e3fe UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [D:\_Release-4.26\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1046]
0x00007ffba37843d0 UE4Editor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [D:\_Release-4.26\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:878]
0x00007ffbcc9fe858 USER32.dll!UnknownFunction []
0x00007ffbcc9fe299 USER32.dll!UnknownFunction []
0x00007ffba379fa04 UE4Editor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [D:\_Release-4.26\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:130]
0x00007ff63a668857 UE4Editor.exe!FEngineLoop::Tick() [D:\_Release-4.26\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:4748]
0x00007ff63a6811dc UE4Editor.exe!GuardedMain() [D:\_Release-4.26\Engine\Source\Runtime\Launch\Private\Launch.cpp:169]
0x00007ff63a6812ba UE4Editor.exe!GuardedMainWrapper() [D:\_Release-4.26\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:137]
0x00007ff63a69528d UE4Editor.exe!WinMain() [D:\_Release-4.26\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:268]
0x00007ff63a697faa UE4Editor.exe!__scrt_common_main_seh() [D:\agent\_work\9\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
0x00007ffbcbda7034 KERNEL32.DLL!UnknownFunction []
0x00007ffbcdb3d241 ntdll.dll!UnknownFunction []