kcms:keys: fix changing command text or path
requested to merge ngraham/plasma-desktop:fix-changing-shortcuts-kcm-command-name-or-path into master
The code was trying to change an item by its ID that is dynamically instantated within a delegate; that won't work.
Instead we need to change a top-level property on the delegate itself and bubble that change down to its contentItem.
BUG: 481825 FIXED-IN: 6.0.1