feat: changes required for Campaigns rearchitecture

[dkoo]

All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

All changes required for the Campaigns Rearchitecture initiative. Also requires Automattic/newspack-plugin#2558 and Automattic/newspack-popups#1192.

How to test the changes in this Pull Request:

There should be no functional changes as a result of this changeset, but it does remove the hidden AMP client ID field which was previously a requirement for the Campaigns Lightweight API, since client ID is no longer needed for Campaigns segmentation APIs.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?

[matticbot]

🎉 This PR is included in version 1.74.0-alpha.1 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[matticbot]

🎉 This PR is included in version 1.74.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀