Create an array of formValidators to conditionally pass in maxLength to it when it is set

src/app/shared/dialogs/prompt-dialog/prompt-dialog.component.ts

@@ -65,11 +65,13 @@ export class PromptDialogComponent implements OnInit {
 
   ngOnInit() {
     // Deafults for input form
+    let formValidators = [Validators.required];
+    if (this.maxLength) {
+      formValidators.push(Validators.maxLength(this.maxLength));
+    }
+
     this.inputForm = new FormGroup({
-      value: new FormControl(this.initialValue || '', [
-        Validators.maxLength(this.maxLength),
-        Validators.required,
-      ]),
+      value: new FormControl(this.initialValue || '', formValidators),
     });
   }