refactor(UserRepCreateDto): Die Eigenschaften validFrom und validTo wurden zu not-null.

DigitalData.UserManager.API/ClientApp/user_manager_ui/src/app/pages/user-representation/user-representation.component.ts

@@ -100,6 +100,8 @@ export class UserRepresentationComponent extends BasePageComponent implements Af
           userId: this.slUserId,
           groupId: this.slGroupId,
           repUserId: this.slRepUserId,
+          validFrom: new Date(),
+          validTo: new Date(new Date().setDate(new Date().getDate() + 7)) //after one week
         }
         this.userRepService.create(newUserRep).subscribe({
           next: (response) => {