refs https://github.com/TryGhost/Ghost/issues/11965
- updated the `{{gh-format-post-time}}` helper that is used in editor status and in post settings menu email sub-menu for displaying email sent time
refs https://github.com/TryGhost/Ghost/issues/10318
- API has been updated to still work with `active_timezone` for backwards compatibility but it makes sense for the client to match the underlying settings keys