Fix changeAuthenticatorAppRouter

The /change-authenticator-app is currently accessible in production
which should not be happening seeing as MFA method management is
not live yet.
This ensures this route is behind the supportChangeMfa flag, so that the
page is only accessible once the MFA MM feature is live.

src/app.ts

@@ -187,8 +187,8 @@ async function createApp(): Promise<express.Application> {
     app.use(addMfaMethodRouter);
     app.use(addMfaMethodAppRouter);
     app.use(addMfaMethodSmsRouter);
+    app.use(changeAuthenticatorAppRouter);
   }
-  app.use(changeAuthenticatorAppRouter);
   app.use(trackAndRedirectRouter);
 
   // Router for all previously used URLs, that we want to redirect on