services: Log-in services now require "pam_loginuid".

services: Log-in services now require "pam_loginuid".

Fixes <https://bugs.gnu.org/35553>.
Reported by Bruno Haible <bruno@clisp.org>.

* gnu/services/base.scm (login-pam-service): Pass #:login-uid? #t to
'unix-pam-service'.
* gnu/services/ssh.scm (lsh-pam-services, openssh-pam-services):
Likewise.
* gnu/services/xorg.scm (slim-pam-service): Likewise.
(gdm-pam-service): Likewise for "gdm-autologin" and "gdm-password".
* gnu/tests/base.scm (run-basic-test)["getlogin on tty1"]: New test.
* gnu/tests/ssh.scm (run-ssh-test): Add #:test-getlogin? parameter.
["getlogin"]: New test.
(%test-dropbear): Pass #:test-getlogin? #f.