Crash when enabling Nanite on a Mesh using an OptimusDeformer

When a skeletal mesh has a deformer present and then nanite support is enabled and applied. (the deformer in question was hsasset://DeformerGraph/Deformers/DG_LinearBlendSkin_Morph_Cloth_RecomputeNormals)

This causes a crash within FSkeletalMeshDeformerHelpers::GetClothBuffersForReading() as its doing a static cast on the FSkeletalMeshObject and is assuming its a FSkeletalMeshObjectGPUSkin where as its actually a FSkeletalMeshObjectNanite. It then tries to use the incorrectly converted object and crashes.

Steps to Reproduce

Open Skeletal Mesh

Apply "DG_LinearBlendSkin_Morph_Cloth_RecomputeNormals" to the deformer variable in the asset details window

Toggle on "Enable nanite support" under the nanite sub catagory

Click apply settings at the end of the nanite sub catagory

> UnrealEditor-Engine.dll!FSkeletalMeshObjectGPUSkin::GetBaseSkinVertexFactory(int LODIndex, int ChunkIdx) Line 1946 C++
UnrealEditor-Engine.dll!FSkeletalMeshDeformerHelpers::GetClothBuffersForReading(const FSkeletalMeshObject * InMeshObject, int InLodIndex, int InSectionIndex, unsigned int InFrameNumber, bool bInPreviousFrame) Line 65 C++
UnrealEditor-OptimusCore.dll!FOptimusClothDataProviderProxy::GatherPermutations(FComputeDataProviderRenderProxy::FPermutationData & InOutPermutationData) Line 190 C++
UnrealEditor-ComputeFramework.dll!FComputeGraphTaskWorker::SubmitWork(FComputeContext & Context) Line 187 C++
UnrealEditor-Renderer.dll!FScene::Update(FRDGBuilder & GraphBuilder, const FScene::FUpdateParameters & Parameters) Line 6556 C++
UnrealEditor-Renderer.dll!FSceneRenderer::OnRenderBegin(FRDGBuilder & GraphBuilder, const FSceneRenderUpdateInputs * SceneUpdateInputs) Line 4074 C++
UnrealEditor-Renderer.dll!FDeferredShadingSceneRenderer::RenderHitProxies(FRDGBuilder & GraphBuilder, const FSceneRenderUpdateInputs * SceneUpdateInputs) Line 624 C++
UnrealEditor-Renderer.dll!RenderViewFamily_RenderThread(FRDGBuilder & GraphBuilder, FSceneRenderer * Renderer, const FSceneRenderUpdateInputs * SceneUpdateInputs) Line 4906 C++
[Inline Frame] UnrealEditor-Renderer.dll!FRendererModule::BeginRenderingViewFamilies::__l116::::operator()(FRDGBuilder &) Line 5207 C++
UnrealEditor-Renderer.dll!`FRendererModule::BeginRenderingViewFamilies'::`116'::::(FRDGBuilder & GraphBuilder, const FSceneRenderFunctionInputs & Inputs) Line 5209 C++
[Inline Frame] UnrealEditor-Renderer.dll!UE::Core::Private::Function::TFunctionRefBase,bool __cdecl(FRDGBuilder &,FSceneRenderFunctionInputs const &)>::operator()(FRDGBuilder &) Line 414 C++
UnrealEditor-Renderer.dll!FSceneRenderProcessor::Execute::__l30::::operator()(FRHICommandListImmediate & RHICmdList) Line 894 C++
UnrealEditor-RenderCore.dll!ExecuteCommand(FRHICommandList * RHICmdList, const TVariant,TUniqueFunction,TUniqueFunction> & Function, const FRenderCommandTag & Tag) Line 1540 C++
[Inline Frame] UnrealEditor-RenderCore.dll!FRenderThreadCommandPipe::ExecuteCommands::__l2::::operator()(TVariant,TUniqueFunction,TUniqueFunction> &&) Line 1937 C++
UnrealEditor-RenderCore.dll!UE::RenderCommandPipe::FCommandList::ConsumeCommands<`FRenderThreadCommandPipe::ExecuteCommands'::`2'::>(const FRenderThreadCommandPipe::ExecuteCommands::__l2:: & Lambda) Line 431 C++
[Inline Frame] UnrealEditor-RenderCore.dll!FRenderThreadCommandPipe::ExecuteCommands(UE::RenderCommandPipe::FCommandList &) Line 1935 C++
UnrealEditor-RenderCore.dll!FRenderThreadCommandPipe::EnqueueAndLaunch::__l5::::operator()() Line 1924 C++
[Inline Frame] UnrealEditor-RenderCore.dll!UE::Core::Private::Function::TFunctionRefBase,void __cdecl(void)>::operator()() Line 414 C++
[Inline Frame] UnrealEditor-RenderCore.dll!TFunctionGraphTaskImpl::DoTaskImpl(TUniqueFunction &) Line 1101 C++
[Inline Frame] UnrealEditor-RenderCore.dll!TFunctionGraphTaskImpl::DoTask(ENamedThreads::Type) Line 1094 C++
UnrealEditor-RenderCore.dll!TGraphTask>::ExecuteTask() Line 696 C++
UnrealEditor-Core.dll!UE::Tasks::Private::FTaskBase::TryExecuteTask() Line 518 C++
[Inline Frame] UnrealEditor-Core.dll!FBaseGraphTask::Execute(TArray> &) Line 495 C++
UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread(int QueueIndex, bool bAllowStall) Line 791 C++
UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 680 C++
UnrealEditor-RenderCore.dll!RenderingThreadMain(FEvent * TaskGraphBoundSyncEvent) Line 260 C++
UnrealEditor-RenderCore.dll!FRenderingThread::Run() Line 420 C++
UnrealEditor-Core.dll!FRunnableThreadWin::Run() Line 159 C++
UnrealEditor-Core.dll!FRunnableThreadWin::GuardedRun() Line 71 C++
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