Sample is truncating BackingMemory buffer size to 4GB

[mapodaca-nv]

The following code truncates the maximum backing store size to 4GB when allocating the buffer.
If the minimum requested size is larger than the truncated max size, then this will cause functional errors.

WorkGraphsMeshNodeSample/meshNodeSample/workgraphrendermodule.cpp

Line 482 in f3486b1

static_cast<uint32_t>(memoryRequirements.MaxSizeInBytes),