Crash when trying to export unsupported Paragon Skeletal Mesh asset in 4.23

When the user tries to export the Skeletal Mesh of TwinBlast (a paragon character that can be purchased off the marketplace) in 4.23. As of the time of logging this bug it is not supported in 4.23, but there isn't a warning/explanation prompt when trying to Export an asset that isn't supported in the engine being used.

Found in 4.23.0 CL#8386587

1. Create a new 4.22 project.
2. Include the Paragon:TwinBlast marketplace asset into the project.
3. Open a copy of the project in 4.23.
4. In the 4.23 copy of the project export the Skeletal Mesh uasset as an .fbx (Right click->Asset Actions->Export).

Results: The engine crashes when trying to export the Skeletal Mesh Component.

Expected: There is a warning that prevents the user from trying to export.

LoginId:9a8d08644d702ac44f074090ac311686
EpicAccountId:580fb2844ad145d79dff08f42acea7c6

Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 614] Array index out of bounds: 61488 from an array of size 56047

UE4Editor_Core!FWindowsErrorOutputDevice::Serialize() [d:\build\++ue4\sync\engine\source\runtime\core\private\windows\windowserroroutputdevice.cpp:79]
UE4Editor_Core!FOutputDevice::LogfImpl() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:71]
UE4Editor_Core!AssertFailedImplV() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:101]
UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:445]
UE4Editor_UnrealEd!DispatchCheckVerify<void,<lambda_0b8ba242c52b8a39a198da9cf75f620f> >() [d:\build\++ue4\sync\engine\source\runtime\core\public\misc\assertionmacros.h:165]
UE4Editor_UnrealEd!UnFbx::FFbxExporter::CreateMesh() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\fbx\fbxskeletalmeshexport.cpp:286]
UE4Editor_UnrealEd!UnFbx::FFbxExporter::ExportSkeletalMeshToFbx() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\fbx\fbxskeletalmeshexport.cpp:672]
UE4Editor_UnrealEd!UnFbx::FFbxExporter::ExportSkeletalMesh() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\fbx\fbxmainexport.cpp:1202]
UE4Editor_UnrealEd!USkeletalMeshExporterFBX::ExportBinary() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\editorexporters.cpp:2087]
UE4Editor_Engine!UExporter::ExportToArchive() [d:\build\++ue4\sync\engine\source\runtime\engine\private\unrealexporter.cpp:164]
UE4Editor_Engine!UExporter::RunAssetExportTask() [d:\build\++ue4\sync\engine\source\runtime\engine\private\unrealexporter.cpp:359]
UE4Editor_AssetTools!UAssetToolsImpl::ExportAssetsInternal() [d:\build\++ue4\sync\engine\source\developer\assettools\private\assettools.cpp:2392]
UE4Editor_AssetTools!UAssetToolsImpl::ExportAssetsWithDialog() [d:\build\++ue4\sync\engine\source\developer\assettools\private\assettools.cpp:1190]
UE4Editor_ContentBrowser!FAssetContextMenu::ExecuteExport() [d:\build\++ue4\sync\engine\source\editor\contentbrowser\private\assetcontextmenu.cpp:2399]
UE4Editor_ContentBrowser!TBaseSPMethodDelegateInstance<0,FAssetContextMenu,0,void __cdecl(void)>::ExecuteIfSafe() [d:\build\++ue4\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:369]
UE4Editor_Slate!SMenuEntryBlock::OnClicked() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:1030]
UE4Editor_Slate!SMenuEntryBlock::OnMenuItemButtonClicked() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:981]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,0,FReply __cdecl(void)>::Execute() [d:\build\++ue4\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:293]
UE4Editor_Slate!SButton::ExecuteOnClick() [d:\build\++ue4\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:379]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build\++ue4\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:303]
UE4Editor_Slate!SMenuEntryButton::OnMouseButtonUp() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:385]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_6c1f6b862bcfb82ea6dcab28fbcc9463> >() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:273]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5707]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6312]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6285]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1880]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2332]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1560]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:790]
user32
user32
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:130]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launchengineloop.cpp:4169]
UE4Editor!GuardedMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launch.cpp:173]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:147]
UE4Editor!WinMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:279]
UE4Editor!__scrt_common_main_seh() [d:\agent\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll