test: drop brittle assertions

[petrutlucian94]

"validate_cis_hardening" explicitly checks the number of warnings and successful tests, which is extremely brittle. The microk8s CI is currently failing because of this.

We'll loosen those assertions and only check for expected failures.

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[petrutlucian94]

It was decided to actually keep those assertions and pin Pytest.

The following check produces different results when using versions other than the pinned one.

microk8s-core-addons/addons/cis-hardening/cfg/cis-1.24-microk8s/etcd.yaml

Line 13 in f2716f1

audit: "/bin/ps -ef | /bin/grep $etcdbin | /bin/grep -v grep"