Refactor UserImporter username cleanup
Refactor UserImporter username cleanup

This will also protect against combinations of LTR and RTL characters, just in case.

WikiEducationFoundation/WikiEduDashboard,sejalkhatri/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,sejalkhatri/WikiEduDashboard,sejalkhatri/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,sejalkhatri/WikiEduDashboard,sejalkhatri/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard