Wrong emails sent when accounts are manually created from admin

Problem/Motivation

When administrators manually create new accounts from /admin/people/create and:

1. Unchecks "Notify user of new account" the system still sends an welcome email to the new account owner.
2. Checks "Notify user of new account" - Two emails are sent: drupal core default welcome mail and another mail from the module. The former contains the single use link which does not work. (only if account created is blocked)

Steps to reproduce

1. Setup a new clean Drupal 9 website
2. Install and configure instance to send emails (i.e mailsystem + smtp modules)
3. Install and configure user_registrationpassword module. In /admin/config/people/accounts configure option "Require a verification email, but let users set their password directly on the registration form."

Case #1 - Manually create a new account and uncheck "Notify user of new account".

Expected outcome: There shouldn't be any email sent
Actual outcome: The system sends the welcome email

See email-from-module.txt

Case #2 - Manually create a new account and check "Notify user of new account".

Two emails are sent:

1) From module (email shown above)
2) From Drupal core:

See email-from-core.txt

When attempting to access the link http://drupal9.localhost/user/reset/7/1656521212/Yq6SA7UIW8xC68lfUOa04At... - it shows "Access denied" because the account is blocked yet (it wasn't yet enabled). (if newly created account is blocked which doesn't make sense)

Proposed resolution

The module should check the field 'notify' is present and enabled in the form and if

1) unchecked should not send an email at all - it assumes the administrator will use other means to notify the user
2) checked should only send the email from the module and not the email sent by core

Remaining tasks

Implement suggested fix. It affects both 1.x and 2.x branches.