We've seen from experience that people do end up with broken files, due to user-modifications and whatnot. Corrupting it further won't make things better for the user. Contributes to issue CURA-8212.
Don't know how this passed code review. I think I was the one to review it, too.
CURA-8212
Makes sure to upgrade the old twotrees_bluer into the new two_trees_bluer definition. CURA-8212