NSS and PAM integration tests time out on s390x on autopkgtest.ubuntu.com

[adombeck]

2392s *** Test killed with quit: ran too long (11m0s).
2392s FAIL	github.com/ubuntu/authd/nss/integration-tests	660.046s
[...]
2405s *** Test killed with quit: ran too long (11m0s).
2405s FAIL	github.com/ubuntu/authd/pam/integration-tests	660.103s

Examples:

• https://autopkgtest.ubuntu.com/results/autopkgtest-resolute/resolute/s390x/a/authd/20260319_000954_2fd12@/log.gz
• https://autopkgtest.ubuntu.com/results/autopkgtest-resolute/resolute/s390x/a/authd/20260318_180830_e8ecd@/log.gz