fix: improves how code access user-agent in the headers (RocketChat#37493)

Author: lucas-a-pelegrino

.changeset/healthy-rabbits-sip.md

@@ -0,0 +1,5 @@
+---
+"@rocket.chat/meteor": patch
+---
+
+Fixes an issue where `user-agent` is not properly extracted from the DDP connection headers

apps/meteor/ee/server/lib/deviceManagement/session.ts

@@ -3,7 +3,6 @@ import { Users } from '@rocket.chat/models';
 import { Accounts } from 'meteor/accounts-base';
 import { Meteor } from 'meteor/meteor';
 import moment from 'moment';
-import type { Headers } from 'node-fetch';
 import { UAParser } from 'ua-parser-js';
 
 import * as Mailer from '../../../../app/mailer/server/api';
@@ -67,9 +66,9 @@ export const listenSessionLogin = () => {
 			username,
 			emails: [{ address: email }],
 		} = user;
-		// TODO: Find why the httpheaders is being casted to IncomingHttpHeaders instead of Headers
-		const userAgentString = connection?.httpHeaders && (connection.httpHeaders as unknown as Headers).get('user-agent');
-		const { browser, os, device, cpu, app } = await uaParser(userAgentString || '');
+
+		const userAgentString = connection?.httpHeaders?.['user-agent'] ?? '';
+		const { browser, os, device, cpu, app } = await uaParser(userAgentString);
 
 		const mailData = {
 			name,