When processing volume names for the File Browser sidebar lists we are properly handling Windows "wide" characters (UTF-16) as long as they are single wide characters, so below U+FFFF. For characters above this value we get a pair of UTF-16, and end up trying to convert each to UTF-8 as separate UTF-32 values. The result is blank output and a console error that "surrogates not allowed." This PR just does this conversion correctly using utfconv. Pull Request: https://projects.blender.org/blender/blender/pulls/131763