ref https://github.com/TryGhost/Product/issues/4110
Made this change to increase clarity in data export
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### <samp>🤖 Generated by Copilot at 6c0508d</samp>
Renamed a column in posts export data and updated the corresponding test
case. This change makes the export data more consistent and clear for
users who have different member features enabled.
no issue
Bookshelf by default returns an empty model when requesting .related('email') for a post without an email. So we need to be a bit smarter to know if a post has an email or not. This fixed an issue where we always showed 'published and emailed' instead of 'published only'.
Since this change also included some changes to test helpers, it also made some changes to the email service because coverage dropped below 100% as a result of fixing the .related method mocking. Ideally we want to move test test helpers to a seperate package in the future.
