refactor: Lengthen the time it takes for a newsletter request to expire to 24h

It appears that a lot of users are having their newsletter subscription request links expire before they can get to them. This commit updates the time it takes for such a request to expire from 3600 seconds (1 hour) to 86400 seconds (1 day).

Related to #157.

requested review from @anarcat

assigned to @stephen

resolved all threads

added 1 commit

• 1719beef - Apply 1 suggestion(s) to 1 file(s)

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added 6 commits

• 1719beef...f7667219 - 4 commits from branch main
• 0a82ba45 - Merge branch 'main' into 24h-newsletter-request-expiry
• 4d48e7aa - Merge branch '24h-newsletter-request-expiry' of...

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resolved all threads

mentioned in commit 9083a43a

merged