[AAE-21797] Datetime widget Min/Max values are checked on a field that is not required (#9524)

* [AAE-21797] Datetime widget Min/Max values are checked on a field that is not required

* update test

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

@@ -313,6 +313,33 @@ describe('FormFieldModel', () => {
         expect(form.values['datetime']).toEqual(expectedDateTimeFormat);
     });
 
+    it('should set the value to null when the value is null', () => {
+        const form = new FormModel();
+        const field = new FormFieldModel(form, {
+            fieldType: 'FormFieldRepresentation',
+            id: 'datetime',
+            name: 'date and time',
+            type: 'datetime',
+            value: null,
+            required: false,
+            readOnly: false,
+            params: {
+                field: {
+                    id: 'datetime',
+                    name: 'date and time',
+                    type: 'datetime',
+                    value: null,
+                    required: false,
+                    readOnly: false
+                }
+            },
+            dateDisplayFormat: 'YYYY-MM-DD HH:mm'
+        });
+
+        expect(field.value).toBe(null);
+        expect(form.values['datetime']).toEqual(null);
+    });
+
     it('should parse the checkbox set to "true" when it is readonly', () => {
         const form = new FormModel();
         const field = new FormFieldModel(form, {

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

@@ -451,7 +451,7 @@ export class FormFieldModel extends FormWidgetModel {
                     this.value = DateFnsUtils.formatDate(new Date(), this.dateDisplayFormat);
                 }
 
-                const dateTimeValue = new Date(this.value);
+                const dateTimeValue = this.value !== null ? new Date(this.value) : null;
 
                 if (isValidDate(dateTimeValue)) {
                     this.form.values[this.id] = dateTimeValue.toISOString();