Remove the JS specific code related to the deprecated render element PasswordConfirm

Problem/Motivation

In 📌 Replace confirm password field with show/hide functionality Needs work we deprecated \Drupal\Core\Render\Element\PasswordConfirm to remove the requirement to enter the password twice, but the related js code is still there.

Steps to reproduce

Proposed resolution

Remove the PasswordConfirm from the js specific code. One such file is core/modules/user/user.js which has code related to PasswordConfirm.

Merge request link

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet