CI: Try a full ssh connection on hosts instead of only checking the port

[VannTen]

What type of PR is this?
/kind flake

What this PR does / why we need it:
If we only try the port, we can try to connect in the playbook which is
executed next even though the managed node has not yet completed it's
boot-up sequence ("System is booting up. Unprivileged users are not
permitted to log in yet. Please come back later. For technical details,
see pam_nologin(8).")

wait_for_connection works, but we need to take care to exclude errors
which are not 'unreachable' (in particular, python-less hosts would
failed that task, but only after ssh succeded).

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:
See and example of the problem : https://gitlab.com/kargo-ci/kubernetes-sigs-kubespray/-/jobs/10754918165 (look for 'System is booting up')

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: VannTen

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[VannTen]

/retest

[tico88612]

If this worked, #12359 can fixed

[VannTen]

This does not work yet, because for some reason wait_for_connection use a local connection

PLAY [Wait until SSH is available] *********************************************
Friday 25 July 2025  08:56:28 +0000 (0:00:00.024)       0:00:16.860 *********** 
[WARNING]: Reset is not implemented for this connection
wait_for_connection: attempting ping module test
<10.11.207.170> ESTABLISH LOCAL CONNECTION FOR USER: root
<10.11.207.170> EXEC /bin/sh -c 'echo ~root && sleep 0'
<10.11.207.170> EXEC /bin/sh -c '( umask 77 && mkdir -p "` echo /root/.ansible/tmp `"&& mkdir "` echo /root/.ansible/tmp/ansible-tmp-1753433788.737992-180-50952141315317 `" && echo ansible-tmp-1753433788.737992-180-50952141315317="` echo /root/.ansible/tmp/ansible-tmp-1753433788.737992-180-50952141315317 `" ) && sleep 0'
wait_for_connection: attempting ping module test
<10.11.18.230> ESTABLISH LOCAL CONNECTION FOR USER: root