desktop: drop noctalia dotfiles and inventory vars

Remove the noctalia config tree and its desktop_void_dotfiles entry,
plus the unused noctalia_bar_monitors / noctalia_screen_overrides vars.
Not used by any role.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ansible/inventory/group_vars/desktop.yml

@@ -182,11 +182,6 @@ desktop_sway_dotfiles:
     dest: .config/alacritty/
     mode: preserve
 
-noctalia_bar_monitors:
-  - DP-1
-
-noctalia_screen_overrides: []
-
 desktop_flatpak_packages:
   - be.alexandervanhee.gradia
   - ch.protonmail.protonmail-bridge