Update pt_BR.po

This update improves the translation of system messages from English to Portuguese Brazil. The goal is to provide a more accurate, consistent, and user-friendly translation for Portuguese-speaking users encountering these error messages in the system. The previous translation was incomplete and inconsistent in certain cases, and this update ensures that all messages are translated appropriately and maintain technical accuracy. The changes also address some missing or incorrect terms, ensuring a better localization experience for end-users.