feat: auto-refresh widget colors when the theme is change by the user

refilc/android/app/src/main/java/hu/refilc/naplo/widget_timetable/WidgetTimetableDataProvider.java

@@ -248,6 +248,9 @@ public class WidgetTimetableDataProvider implements RemoteViewsService.RemoteVie
     }
 
     private void initData() {
+        // refresh theme
+        fullTheme = getFullTheme(context);
+
         rday = WidgetTimetable.selectDay(context, appWidgetId, 0, false);
 
         day_subjects.clear();