ci: only specify scene name once in UI preview test (#34752)

remove this garbage

.github/workflows/ui_preview.yaml

@@ -84,7 +84,7 @@ jobs:
         run: >-
           sudo apt-get install -y imagemagick
 
-          scenes="homescreen settings_device settings_software settings_toggles settings_developer offroad_alert update_available prime onroad onroad_disengaged onroad_override onroad_sidebar onroad_wide onroad_wide_sidebar onroad_alert_small onroad_alert_mid onroad_alert_full driver_camera body keyboard keyboard_uppercase"
+          scenes=$(find ${{ github.workspace }}/pr_ui/*.png -type f -printf "%f\n" | cut -d '.' -f 1 | grep -v 'pair_device')
           A=($scenes)
 
           DIFF=""