Fix sub-second timing comparison error for Devise confirmation period

On databases such as MySQL, it's possible to get into a timing comparison error if the value of Confirmable#confirmation_sent_at is within a second of 0.days.ago. This is possible mostly in specs that test this behavior and most likely not happening in practice. The result of this error causes a user to be deemed active when it should be inactive. To prevent this error, we explicitly check the configuration setting to be 0.days.ago.

Closes gitlab-org/gitlab-ee#2362

changed milestone to %9.2

assigned to @rymai

Submitted a fix upstream to Devise: https://github.com/plataformatec/devise/pull/4529

added ~149423 test labels

assigned to @smcgivern

@stanhu great investigation, thanks 🙂

assigned to @stanhu

assigned to @smcgivern

approved this merge request

resolved all discussions

mentioned in commit 09e2c1af

merged

mentioned in issue #31934 (closed)

mentioned in commit 848466ee

Picked into 9-2-stable, will go into 9.2.0-rc1.