[Forwardport] Fix #10687 - Product image roles disappearing

[eduard13]

Original PR #15606

To fix #10687 - adds the 'types' key to the images array to provide existing image roles, which are reset after clearMediaAttribute() is called.

Description

This PR is to fix the issue outlined in #10687 - image roles being removed when saving by the ProductRepository.

Fixed Issues (if relevant)

1. Product image roles randomly disappear #10687: Product image roles randomly disappear

Manual testing scenarios

1. Initially save a product using the ProductRepostory, setting an image in the gallery with roles.
2. Save the product again, without setting the media gallery at all. Roles should persist after second save.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @eduard13. Thank you for your contribution
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[magento-engcom-team]

Hi @VladimirZaets, thank you for the review.
ENGCOM-2751 has been created to process this Pull Request

[magento-engcom-team]

Hi @eduard13. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.