Translation updates * pt-BR (#6490)
Project tests updated.
Fixed: gantt broken when no due date on project issues and versions.
Fixed: error on mail notification when adding an invalid file (#6452).
Fixes broken filter clearing links on gantt and calendar (#6473).
Translation updates * cs (#6471)
Refactor: move NewsController#preview to PreviewsController#news
Translation updates * cs (#6471) * ja (#6465) * zh-TW (#6466)
Refactor: move #destroy_comment method to CommentsController#destroy
Translation update * ru