User account default setting for cancel confirm is not used

Problem/Motivation

There is a user setting named notify.cancel_confirm, which should be used a default value for "Account cancellation confirmation". Unfortunately it has no effect. Besides that you are not able to change this default setting in the account settings form (admin/config/people/accounts).

This is a follow up issue of https://www.drupal.org/project/drupal/issues/2854884 → .

Proposed resolution

1. Use the user setting named notify.cancel_confirm as default value for the user cancel form.
2. Provide a checkbox in account settings (admin/config/people/accounts) under "When cancelling a user account", with a note that this can be overridden by users with sufficient permissions.