uid is always supplied so remove unused code path
uid is always supplied so remove unused code path

https://github.com/radiasoft/sirepo/pull/3352#discussion_r580381252

mkeilman/sirepo,radiasoft/sirepo,radiasoft/sirepo,radiasoft/sirepo,radiasoft/sirepo,mkeilman/sirepo,mkeilman/sirepo,mkeilman/sirepo,radiasoft/sirepo