docs: Update online-offline-events.md to reflect nodeIntegration required (#21707)

* Update online-offline-events.md

NodeIntegration is required for online/offline and the default changed, so the example should reflect the need for that config

* chore: fix lint warning

Co-authored-by: Cheng Zhao <zcbenz@github.com>

docs/tutorial/online-offline-events.md

@@ -54,7 +54,7 @@ const { app, BrowserWindow, ipcMain } = require('electron')
 let onlineStatusWindow
 
 app.on('ready', () => {
-  onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false })
+  onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false, webPreferences: { nodeIntegration: true } })
   onlineStatusWindow.loadURL(`file://${__dirname}/online-status.html`)
 })