[Backport] #15308 removed extraneous margin

[gelanivishal]

Original Pull Request

#15936
removed extraneous margin and compensated padding and set both to 0, which creates the same effect

Description

Change in the theme which gives the same effect, but removes the negative margin which was compensated with a padding.

Fixed Issues (if relevant)

1. extraneous margins on product list and product list items #15308: extraneous margins on product list and product list items

Manual testing scenarios

1. open list view of products on a page
2. inspect the list .column.main .product-items and one product .products-list .product-item
3. check if the negative margin and positive padding are replaced by 0 and if the styling is still correct

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 @gelanivishal. Thank you for your contribution.
We will aim to release these changes as part of 2.1.15.
Please check the release notes for final confirmation.