shortcutcontroller: Unref shortcut proper

g_list_model_get_item() is transfer full, so we need to
unref everything that is acquired through it.
5 jobs for gbsneto/shortcuts-rebased in 12 minutes and 6 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #300511
fedora-x86_64

00:03:59

passed #300512
win32
msys2-mingw32

00:12:05

 
  Flatpak
manual #300513
allowed to fail manual
flatpak-manual:demo
manual #300515
allowed to fail manual
flatpak-manual:icon-browser
manual #300514
allowed to fail manual
flatpak-manual:widget-factory