Increase pipeline freshness check from 8 to 12 hours

What does this MR do and why?

Increases the pipeline freshness check from 8 to 12 hours.

Slack conversation (internal):

There have been relatively straightforward and isolated MRs where it took me several days to merge because one flaky job prevented the merge.

https://handbook.gitlab.com/handbook/values/#freedom-and-responsibility-over-rigidity

Freedom and responsibility over rigidity

When possible, we give people the responsibility to make a decision and hold them accountable for that, instead of imposing rules and approval processes. You should have clear objectives and the freedom to work on them as you see fit. Freedom and responsibility are more efficient than rigidly following a process, or creating interdependencies, because they enable faster decision velocity and higher rates of iteration.

This is a 2-way door decision. We can easily revert it.

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