[BUGFIX] Remove all restrictions in user creation command

Implement what is already commented by removing all restrictions when
comparing given username with all existing usernames. Even the username
of a deleted or disabled user must not be reused.

Resolves: #100729
Releases: main, 12.4
Change-Id: I85c314b2c4f6c8539e344e64371c631f29ab9db0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84783


Tested-by: core-ci <typo3@b13.com>
Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>