readline: check for null input in question()

question() checks for objects passed as the recently added options
argument. This commit improves that logic to also check for null.

PR-URL: https://github.com/nodejs/node/pull/37089


Reviewed-By: Zijian Liu <lxxyxzj@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>