chore: consistent naming in externals

apps/electron/src/main.js

@@ -14,7 +14,7 @@ const {
   trayIcon,
   appIcon,
   getServerUrl,
-} = require('./external.js');
+} = require('./externals.js');
 
 if (!isProduction) {
   console.log(`Electron running in ${env} environment`);

apps/electron/src/menu/applicationMenu.js

@@ -13,7 +13,7 @@ const {
   stylesPath,
   externalPath,
   downloadPath,
-} = require('../external');
+} = require('../externals.js');
 
 /**
  * Creates the application menu