fix(calendar): Fix selection with ngModel #6015

Author: hanastasov

src/app/calendar/calendar.sample.html

@@ -19,7 +19,7 @@ <h4 class="sample-title">Default Calendar</h4>
 
                 </div>
                 <igx-card>
-                    <igx-calendar #calendar weekStart="1" selection="multi" [hideOutsideDays]="false" [monthsViewNumber]="3"></igx-calendar>
+                    <igx-calendar #calendar weekStart="1" selection="multi" [hideOutsideDays]="false" [monthsViewNumber]="3" [(ngModel)]="model"></igx-calendar>
                 </igx-card>
             </div>
 

src/app/calendar/calendar.sample.ts

@@ -9,12 +9,14 @@ import { IgxCalendarComponent, DateRangeDescriptor, DateRangeType } from 'ignite
 export class CalendarSampleComponent implements OnInit {
     @ViewChild('calendar', { static: true }) calendar: IgxCalendarComponent;
     @ViewChild('calendar1', { read: IgxCalendarComponent, static: true }) calendar1: IgxCalendarComponent;
+    public model = null;
+    // public model = null;
 
     ngOnInit() {
         this.calendar.disabledDates = [{
             type: DateRangeType.Specific, dateRange: [
-                new Date(2019, 5, 13),
-                new Date(2019, 5, 27),
+                new Date(2019, 10, 13),
+                new Date(2019, 10, 27),
                 new Date(2019, 5, 30),
                 new Date(2019, 6, 1),
                 new Date(2019, 5, 1),