Bug 1869679 - Mark `nsIWindowsMutexFactory` as a platform specific interface. r=mhughes

Depends on D197555

Differential Revision: https://phabricator.services.mozilla.com/D197556

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/valid-ci-uses.js

@@ -27,6 +27,7 @@ const platformSpecificInterfaces = new Map([
   ["nsITaskbarWindowPreview", "windows"],
   ["nsIWindowsAlertsService", "windows"],
   ["nsIWindowsAlertNotification", "windows"],
+  ["nsIWindowsMutexFactory", "windows"],
   ["nsIWinAppHelper", "windows"],
   ["nsIWinTaskbar", "windows"],
   ["nsIWinTaskSchedulerService", "windows"],