Update app.js (#5452)

change metrics app name

COPYBARA_INTEGRATE_REVIEW=https://github.com/overleaf/overleaf/pull/947 from salleman33:patch-1 052d4aa0a8b4dd88b381d6fed8e94f0a3b9a7fc4

Co-authored-by: Allemand <37148072+salleman33@users.noreply.github.com>
GitOrigin-RevId: fe23c5431402f918bce1c933051bebd5416d5d94

services/real-time/app.js

@@ -1,6 +1,6 @@
 const Metrics = require('@overleaf/metrics')
 const Settings = require('@overleaf/settings')
-Metrics.initialize(Settings.appName || 'real-time')
+Metrics.initialize(process.env.METRICS_APP_NAME || 'real-time')
 const async = require('async')
 
 const logger = require('logger-sharelatex')