BaseDataWindow: Fix season modifier crash

Elwig/Windows/BaseDataWindow.xaml.cs

@@ -142,6 +142,7 @@ namespace Elwig.Windows {
             FillInputs(App.Client);
             ControlUtils.RenewItemsSource(SeasonList, await ctx.Seasons
                 .OrderByDescending(s => s.Year)
+                .Include(s => s.Modifiers)
                 .ToListAsync(), null, ControlUtils.RenewSourceDefault.First);
             var year = (SeasonList.SelectedItem as Season)?.Year;
             ControlUtils.RenewItemsSource(BranchList, await ctx.Branches