In the KDE systems settings, go to “File Associations”.

From there, you’d be seeing a tree of “known types”, go to “inode” and then “directory”, you can add a new program by clicking “Add…” in the “General > Application Preference Order” area.

What’s happening here is that you’re adding a program to handle the “inode/directory” mimetype. Because of that, this change isn’t limited to Konsole, but will also affect other programs.