fix(FormItem): use getPopupContainer default value (#3215)

src/components/Form/src/components/FormItem.vue

@@ -277,7 +277,6 @@
         const { autoSetPlaceHolder, size } = props.formProps;
         const propsData: Recordable<any> = {
           allowClear: true,
-          getPopupContainer: (trigger: Element) => trigger.parentNode,
           size,
           ...unref(getComponentsProps),
           disabled: unref(getDisable),