Remove deprecated demographics birth year offset pref. This change removes the `sync.demographics_birth_year_offset` pref and the associated migration logic from profile prefs to local state. The cleanup was scheduled for after September 2023. Since the pref was never cleared, adds logic to clear the pref and sets the next step to 12 months later for removing the pref itself. Bug: 40240008 Change-Id: I9a0a0b75f4c64f070d96a6be36f6a17ad93b2acb Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7243638 Reviewed-by: Roger McFarlane <rogerm@chromium.org> Commit-Queue: Alexei Svitkine <asvitkine@chromium.org> Auto-Submit: Alexei Svitkine <asvitkine@chromium.org> Cr-Commit-Position: refs/heads/main@{#1557413} NOKEYCHECK=True GitOrigin-RevId: 35246bb42d92a7648958c2fb078c86839d58e21c 2 files changed
