Geometry Cache crashing when loading async in a cooked build

Geometry cahces check if they are in the game thread, which causes a crash when their packages are async loaded in a cooked build.

1. Create an actor with a geometry cache object reference
2. Create another actor that has a soft object reference to the first actor
3. Place the second actor into the level
4. Enable "Async Loading Thread Enabled" in the Package Streaming project settings
5. Create a cooked build and launch it

RESULT

The client will crash on a check in FGeometryCacheStreamingManager::AddGeometryCache(UGeometryCacheTrackStreamable * Cache) Line 228 C++

1. Win64-DebugGame.exe!FGeometryCacheStreamingManager::AddGeometryCache(UGeometryCacheTrackStreamable * Cache) Line 228 C++
2. Win64-DebugGame.exe!FObjectInitializer::PostConstructInit() Line 2770 C++
3. Win64-DebugGame.exe!FObjectInitializer::~FObjectInitializer() Line 2628 C++
4. Win64-DebugGame.exe!StaticConstructObject_Internal(UClass * InClass, UObject * InOuter, FName InName, EObjectFlags InFlags, EInternalObjectFlags InternalSetFlags, UObject * InTemplate, bool bCopyTransientsFromClassDefaults, FObjectInstancingGraph * InInstanceGraph, bool bAssumeTemplateIsArchetype) Line 3088 C++
5. Win64-DebugGame.exe!FAsyncPackage::EventDrivenCreateExport(int LocalExportIndex) Line 3490 C++
6. Win64-DebugGame.exe!FAsyncPackage::ProcessImportsAndExports_Event() Line 3935 C++
7. [Inline Frame] Win64-DebugGame.exe!FAsyncPackage::Event_ProcessImportsAndExports() Line 2981 C++