[Base] Fix UTF-8 fnfp with trailing separator.

[Base] Fix off-by-one in UTF-8 find_name_from_path with trailing
separator.

src/xenia/base/utf8.cc

@@ -589,7 +589,6 @@ std::string find_name_from_path(const std::string_view path,
       return std::string();
     }
     --it;
-    --end;
     padding = 1;
   }