Cancelling password when adding a new user results in error

[smerriman]

1) Go to Users - Add New.
2) Fill in a Username + Email
3) Click Show Password, then click Cancel
4) Click Add New User.

A user won't be created, with the error "ERROR: Please enter a password.", even though the same process works if you skip step 3.

I believe this was caused by [33980], in which case that should have only been applied to editing a user, not creating one.

[SergeyBiryukov]

In 38494:

Users: After [33766], don't reset the password when clicking "Show Password" and then "Cancel" on Add New User screen.

Props smerriman for reporting.
Fixes #37902. See #33419.