Revert "internal/repos: Extract seconds instead of epoch in backoffquery"
Created by: indradhanush
Reverts sourcegraph/sourcegraph#24338
My findings in #24338 were incorrect. The query was always right.
The alert was triggered because GitHub Starburst's syncing was manually disabled. It's last_sync_at has now been set to a date in the future to prevent the alert from triggering.