`safe_VkPipelineCacheCreateInfo` does not copy its pInitialData from `in_struct`

[MathiasMagnus]

The current codegen for vku::safe_VkPipelineCacheCreateInfo does not copy its souce contents, only the source pointer.

void safe_VkPipelineCacheCreateInfo::initialize(const VkPipelineCacheCreateInfo* in_struct,
                                                [[maybe_unused]] PNextCopyState* copy_state) {
    FreePnextChain(pNext);
    sType = in_struct->sType;
    flags = in_struct->flags;
    initialDataSize = in_struct->initialDataSize;
    pInitialData = in_struct->pInitialData;
    pNext = SafePnextCopy(in_struct->pNext, copy_state);
}