Notification history: Enable by default (#49502)

* remove persistNotifications feature flag

* remove unused imports

public/app/features/notifications/NotificationsPage.tsx

@@ -1,8 +1,6 @@
 import React from 'react';
 import { connect, ConnectedProps } from 'react-redux';
 
-import { config } from '@grafana/runtime';
-
 import Page from '../../core/components/Page/Page';
 import { GrafanaRouteComponentProps } from '../../core/navigation/types';
 import { getNavModel } from '../../core/selectors/navModel';
@@ -21,10 +19,6 @@ interface OwnProps extends GrafanaRouteComponentProps {}
 type Props = OwnProps & ConnectedProps<typeof connector>;
 
 export const NotificationsPage = ({ navModel }: Props) => {
-  if (!config.featureToggles.persistNotifications) {
-    return null;
-  }
-
   return (
     <Page navModel={navModel}>
       <Page.Contents>