E2E Test: increase timeout for ssh-keyscan

What does this MR do and why?

Increasing the ssh-keyscan timeout from the default (5s) to 60s, as we suspect that when this command is run against review-apps that it can take longer than 5s which leads to intermittent failures. It can also fail locally if there is a lot of latency in your location.

Context: #433030 (comment 1699673839)

Test still passing against GDK: https://gitlab.com/gitlab-org/gitlab/-/jobs/5780132300#L812

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