[client-backup] set backup-service prod URL

Summary:
Add URL to deployed service.

There is one problem with this, see: [ENG-4852](https://linear.app/comm/issue/ENG-4852/handle-staging-backup-issue).

Depends on D9066

Test Plan: N/A

Reviewers: michal, marcin, bartek

Reviewed By: michal

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D9075

lib/facts/backup-service.js

@@ -1,5 +1,7 @@
 // @flow
 
+import { isDev } from '../utils/dev-utils.js';
+
 type BackupServiceEndpointPath =
   | '/backups'
   | '/backups/:backupID/user_keys'
@@ -37,8 +39,13 @@ const httpEndpoints = Object.freeze({
   },
 });
 
-const config = {
-  url: 'http://localhost:50052',
+const config: {
+  url: string,
+  httpEndpoints: { +[endpoint: string]: BackupServiceHTTPEndpoint },
+} = {
+  url: isDev
+    ? 'https://backup.staging.commtechnologies.org'
+    : 'https://backup.commtechnologies.org',
   httpEndpoints,
 };