restore old light button behavior

watch faces that handle EVENT_LIGHT_BUTTON_UP but not EVENT_LIGHT_BUTTON_DOWN
probably don't want the default EVENT_LIGHT_BUTTON_DOWN LED activation behavior

movement/watch_faces/complication/countdown_face.c

@@ -225,7 +225,7 @@ bool countdown_face_loop(movement_event_t event, movement_settings_t *settings,
             abort_quick_ticks(state);
             movement_move_to_next_face();
             break;
-        case EVENT_LIGHT_BUTTON_UP:
+        case EVENT_LIGHT_BUTTON_DOWN:
             switch(state->mode) {
                 case cd_running:
                     movement_illuminate_led();