Bogus use after move in DataStorm/config test

[pepone]

https://github.com/zeroc-ice/datastorm/blob/fba29e653d53d3493c423ad1f853f4bee15952cd/cpp/test/DataStorm/config/Writer.cpp#L304

Unless I'm mistaken the call to move(topic) is bogus, as it is also used in makeSingleKeyWriter(topic, "elem")

[pepone]

we can do

auto singleKeyWriter = makeSingleKeyWriter(topic, "elem");
w.emplace_back(
    std::move(holder),
    std::move(node),
    std::move(topic),
    std::move(singleKeyWriter));