Add missing import in TriggerNotifications.js (#1345)

Signed-off-by: vikhy-aws <191836418+vikhy-aws@users.noreply.github.com>
(cherry picked from commit 0c816e1)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

public/pages/CreateTrigger/containers/DefineCompositeLevelTrigger/TriggerNotifications.js

@@ -13,6 +13,7 @@ import {
   EuiButtonIcon,
   EuiToolTip,
 } from '@elastic/eui';
+import _ from 'lodash';
 import TriggerNotificationsContent from './TriggerNotificationsContent';
 import { MAX_CHANNELS_RESULT_SIZE, OS_NOTIFICATION_PLUGIN } from '../../../../utils/constants';
 import { titleTemplate } from '../../../../utils/helpers';