fs: remove extraneous assignments in rmdir()

validateRmOptions() doesn't return a value, so this commit
removes the assignment. The options passed to
validateRmdirOptions() are not used again after validation, so
this commit removes the assignment.

PR-URL: https://github.com/nodejs/node/pull/35567


Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>