Bug 1694144 - [remote] Add missing EXPORTED_SYMBOLS export for new module registry.

Differential Revision: https://phabricator.services.mozilla.com/D122475

remote/webdriver-bidi/modules/ModuleRegistry.jsm

@@ -4,6 +4,8 @@
 
 "use strict";
 
+var EXPORTED_SYMBOLS = [];
+
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );