fix(notifications): export notificationSeverities for reuse

The ordered array of constants is exported by the notifications-common
for reusability by other plugins.

Signed-off-by: Marek Libra <marek.libra@gmail.com>

plugins/notifications-backend/src/database/DatabaseNotificationsStore.ts

@@ -25,6 +25,7 @@ import {
 import {
   Notification,
   NotificationSeverity,
+  notificationSeverities,
 } from '@backstage/plugin-notifications-common';
 import { Knex } from 'knex';
 
@@ -49,16 +50,9 @@ const NOTIFICATION_COLUMNS = [
   'saved',
 ];
 
-const severities: NotificationSeverity[] = [
-  'critical',
-  'high',
-  'normal',
-  'low',
-];
-
 export const normalizeSeverity = (input?: string): NotificationSeverity => {
   let lower = (input ?? 'normal').toLowerCase() as NotificationSeverity;
-  if (severities.indexOf(lower) < 0) {
+  if (notificationSeverities.indexOf(lower) < 0) {
     lower = 'normal';
   }
   return lower;
@@ -219,8 +213,8 @@ export class DatabaseNotificationsStore implements NotificationsStore {
     } // or match both if undefined
 
     if (options.minimumSeverity !== undefined) {
-      const idx = severities.indexOf(options.minimumSeverity);
-      const equalOrHigher = severities.slice(0, idx + 1);
+      const idx = notificationSeverities.indexOf(options.minimumSeverity);
+      const equalOrHigher = notificationSeverities.slice(0, idx + 1);
       query.whereIn('severity', equalOrHigher);
     }