False-positive stale import in Cmd interpolation

[jonas-schulze]

When analyzing MORWiki@0.2, ExplicitImports reports unzip being stale:

pkg> activate --temp

pkg> add ExplicitImports

pkg> add MORWiki@0.2

julia> using MORWiki, ExplicitImports

julia> check_no_stale_explicit_imports(MORWiki)

ERROR: StaleImportsException
Module `MORWiki` has stale (unused) explicit imports for:
* `unzip`

However, it is used inside an interpolation:

function register_steelProfile()
    function post_fetch_method(file)
        run(`$(unzip()) -q $file`)
        rm(file)
    end
    #...
end