When Changing datetime-picker format the validations (mix & max) failes and retuns null as value

[lamaSonmez]

After changing the default datetime picker format from mm/dd/yyy to yyyy-mm-dd , the value retuned if not selected from he calender is always null , which causes matDatetimePickerParse to be thrown and validations for minDate and MaxDate fails as well , pleae review the following StackBlitz: https://stackblitz.com/edit/demo-ngx-mat-datetime-picker-s8slds?file=src/app/app.component.ts