Reduce repeated text for `SmoothStep` and its translations

[TheSofox]

Fixes #93044

visual_shader_editor_plugin.cpp had a line that was getting translated more than once. I've edited the file and a lot of translation files to reduce the repeated text.

[RedMser]

The .po files should not be changed and committed by hand, please revert those changes in your PR. They are manually synced by maintainers, as weblate is used by contributors to update the translations.

[TheSofox]

Done!