Crash when IK Anim Node is used in post process blueprint.

If an IK Anim node is used in a post-process animation blueprint when that post-process blueprint is active in persona. It will crash attempting to get dynamically created goal components from an actor that doesn't exist.

• Add an IK Rig anim node into the post-process anim blueprint.
• Add an IK Rig.
• Set a skeletal mesh to point to the post-process.
• Move to the animation view in persona.
• Try to preview a new animation.

[Inlined] TConstSetBitIterator<FDefaultBitArrayAllocator>::

(const TBitArray<FDefaultBitArrayAllocator> &) BitArray.h:1914
[Inlined] TSparseArray::begin() SparseArray.h:1084
[Inlined] TSet::begin() Set.h:1815
[Inlined] UE::Core::Private::TObjectPtrDecayTypeOf::PerformDecayActions(const TSet<…> &) ObjectPtr.h:1342
ObjectPtrDecay<…>(const TSet<…> &) ObjectPtr.h:1700
[Inlined] AActor::GetComponents() Actor.h:3996
AActor::GetComponentsByInterface(TSubclassOf<…>) Actor.cpp:3687
FAnimNode_IKRig::PreUpdate(const UAnimInstance *) AnimNode_IKRig.cpp:272
FAnimInstanceProxy::PreUpdate(UAnimInstance *, float) AnimInstanceProxy.cpp:552
UAnimInstance::PreUpdateAnimation(float) AnimInstance.cpp:682
UAnimInstance::UpdateAnimation(float, bool, EUpdateAnimationFlag) AnimInstance.cpp:602
USkeletalMeshComponent::TickAnimInstances(float, bool) SkeletalMeshComponent.cpp:1523
USkeletalMeshComponent::TickAnimation(float, bool) SkeletalMeshComponent.cpp:1469
USkeletalMeshComponent::InitAnim(bool) SkeletalMeshComponent.cpp:985
UDebugSkelMeshComponent::InitAnim(bool) DebugSkelMeshComponent.cpp:579
USkeletalMeshComponent::SetSkeletalMesh(USkeletalMesh *, bool) SkeletalMeshComponent.cpp:3148
UDebugSkelMeshComponent::SetSkeletalMesh(USkeletalMesh *, bool) DebugSkelMeshComponent.cpp:626
SAnimationSequenceBrowser::OnVisualizeAssetToolTip(const TSharedPtr<…> &, FAssetData &) SAnimationSequenceBrowser.cpp:1605
[Inlined] Invoke(bool (SAnimationSequenceBrowser::*)(const TSharedPtr<…> &, FAssetData &), SAnimationSequenceBrowser *&, const TSharedPtr<…> &, FAssetData &) Invoke.h:66
[Inlined] UE::Core::Private::Tuple::TTupleBase::ApplyAfter(bool (SAnimationSequenceBrowser::*&)(const TSharedPtr<…> &, FAssetData &), SAnimationSequenceBrowser *&, const TSharedPtr<…> &, FAssetData &) Tuple.h:317
TBaseSPMethodDelegateInstance::Execute(const TSharedPtr<…> &, FAssetData &) DelegateInstancesImpl.h:282
[Inlined] TDelegate::Execute(const TSharedPtr<…> &, FAssetData &) DelegateSignatureImpl.inl:613
SAssetViewItem::OnVisualizeTooltip(const TSharedPtr<…> &) AssetViewWidgets.cpp:1769
FSlateUser::UpdateTooltip(const FMenuStack &, bool) SlateUser.cpp:1300
[Inlined] UE::Core::Private::Function::TFunctionRefBase::operator()(FSlateUser &) Function.h:470
FSlateApplication::ForEachUser(TFunctionRef<…>, bool) SlateApplication.cpp:4442
FSlateApplication::TickPlatform(float) SlateApplication.cpp:1632
FSlateApplication::Tick(ESlateTickType) SlateApplication.cpp:1558
FEngineLoop::Tick() LaunchEngineLoop.cpp:5929
[Inlined] EngineTick() Launch.cpp:69
GuardedMain(const wchar_t *) Launch.cpp:198
LaunchWindowsStartup(HINSTANCE__ *, HINSTANCE__ *, char *, int, const wchar_t *) LaunchWindows.cpp:266
WinMain(HINSTANCE__ *, HINSTANCE__ *, char *, int) LaunchWindows.cpp:317