[TASK] Add Sort order to the Related Produt Collection in the Admin P…

[lewisvoncken]

…anel for Related Products

[BACKPORT] - Sort Order for Related Products + [BACKPORT] #15251

Description

The Related Products are not sorted in the admin panel and in the fix of 2.2 only 2 related products are showing in backend

Fixed Issues (if relevant)

1. Only 2 related products are showing in backend . #13720: Only 2 related products are showing in backend

Steps to reproduce

1. Update products related products using csv and update via magento default import.
2. Flush the cache storage and reindexing .
3. Check the frontend and backend

Expected result

1. Updated related products should come in the frontend of product page and backend of product edit page

Actual result

1. The update related products are showing in the frontend . But only 2 related products are showing in the backend and in a incorrect sort order

Apply changes

Now the expected result will be the outcome.

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)

[sidolov]

Let's wait for PR to 2.2-develop