This PR changes the `opts` argument in `SearchUsers()` to be passed by
value instead of by pointer, as its mutations do not escape the function
scope and are not used elsewhere. This simplifies reasoning about the
function and avoids unnecessary pointer usage.
This insight emerged during an initial attempt to refactor
`RenderUserSearch()`, which currently intermixes multiple concerns.
Co-authored-by: Philip Peterson <philip-peterson@users.noreply.github.com>
b0936f4f41