Converted "No Date Provided" to "Null" fitler constant

prs.desktop/Dashboards/Common/DigitalFormsDashboard.xaml.cs

@@ -1133,7 +1133,7 @@ namespace PRSDesktop
                 .And(x => x.FormCompleted).IsLessThan(To.AddDays(1));
             if (Properties.ShowIncompleteForms)
             {
-                completedFilter.Or(x => x.FormCompleted).IsEqualTo(FilterConstant.NoDateProvided);
+                completedFilter.Or(x => x.FormCompleted).IsEqualTo(FilterConstant.Null);
             }
 
             var filter = new Filter<T>(x => x.Form.ID).IsEqualTo(Form!.ID)