[ADF-4460] Fix for empty value upload widget on a form (#4670)

demo-shell/src/app/components/cloud/community/community-task-details-cloud.component.html

@@ -3,7 +3,7 @@
 <div fxLayout="column" fxFill fxLayoutGap="2px">
     <div fxLayout="row" fxFill>
         <div fxLayout="column" fxFlex="80%">
-            <adf-task-form-cloud
+            <adf-cloud-task-form
                 [appName]="''"
                 [taskId]="taskId"
                 (cancelClick)="goBack()"
@@ -11,7 +11,7 @@
                 (taskCompleted)="onTaskCompleted()"
                 (taskUnclaimed)="onUnclaimTask()"
                 (formSaved)="onFormSaved()">
-            </adf-task-form-cloud>
+            </adf-cloud-task-form>
         </div>
         <adf-cloud-task-header fxFlex
             [appName]="''"

lib/core/form/components/widgets/core/form-field.model.ts

@@ -378,7 +378,7 @@ export class FormFieldModel extends FormWidgetModel {
                 if (this.value && this.value.length > 0) {
                     this.form.values[this.id] = this.value.map((elem) => elem.id).join(',');
                 } else {
-                    this.form.values[this.id] = [];
+                    this.form.values[this.id] = null;
                 }
                 break;
             case FormFieldTypes.TYPEAHEAD: