auto login: fix the prompts list after login

The prompts linked to username/password errors, should not be used when typing
login_commands.

Also fix tests of auto-login failures.

Signed-off-by: Rémi Duraffort <remi.duraffort@linaro.org>
15 jobs from auto_login in 13 minutes and 19 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #28503
amd64
dispatcher-debian-10

00:03:37

passed #28501
amd64
dispatcher-debian-9

00:03:05

passed #28504
amd64
server-debian-10

00:02:37

passed #28502
amd64
server-debian-9

00:02:59

 
  Analyze
passed #28505
amd64
black

00:01:11

passed #28507
amd64
code_quality

00:00:25

passed #28506
amd64
codestyle

00:01:06

passed #28510
amd64
job-schema

00:01:20

passed #28508
amd64
pylint

00:02:20

passed #28509
dind amd64 allowed to fail
sast

00:02:51

 
  Build
passed #28513
amd64
amd64/pkg-debian-10

00:02:06

passed #28512
amd64
amd64/pkg-debian-9

00:02:31

passed #28511
amd64
doc

00:02:39

 
  Docker
passed #28514
dind amd64
amd64/lava-dispatcher

00:01:26

passed #28515
dind amd64
amd64/lava-server

00:02:47