I finally got a moment to look at this. The binary with the samples is
being built (you can find it in
$WORKDIR/build/app/bin/x86_64/vulkan_samples), but is not installed.
So if you want to get it packaged for targets you need to adjust the
recipe and add a do_install:append() section that does it (plenty of
examples in poky/meta). Patches welcome.

It's also a bit sad that no one has actually used recipe until now,
otherwise we'd know sooner.

Alex