Increase seat link cron window

What does this MR do and why?

Corrective action, part of https://gitlab.com/gitlab-org/customers-gitlab-com/-/issues/3783 (3/3 short-term actions)

this doubles the window for the SeatLinkRequestWorker (1h randomness to 2 hours), right before the AutoRenewCronJob runs (in CustomersDot).

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