When moving a unique_ptr, you are actually passing the object, not a
reference to the object. So we either std::move with the bare
unique_ptr parameter or we pass a reference. But we should never pass
an rvalue reference for this or we'll make a copy without holding the
tracking (because it was moved)
Fixes https://gitlab.com/kicad/code/kicad/-/issues/16839
(cherry picked from commit b2a25cb59e)