Expose embargo end date

[jwalz]

Purpose

Allow FE to display the Embargo End Date to moderators when they're making moderator-y decisions

Changes

Return the end_date in embargo_end_date when state is APPROVED or PENDING_MODERATION instead of just APPROVED

Note, embargo_end_date is used as a proxy for is_embargoed in many tests, so getting rid of all state-based guards risks requiring a lot of test refactoring.

QA Notes

Please make verification statements inspired by your code and what your code touches.

• Verify
• Verify

What are the areas of risk?

Any concerns/considerations/questions that development raised?

Documentation

Side Effects

Ticket