[Backport] chore: remove extraneous cursor property

[gelanivishal]

Original Pull Request

#15305

Description

cursor is not usable with pointer-events: none. Also this would add the not-allowed cursor which does not make much sense imho.

Manual testing scenarios

1. create a button with the disabled property
2. hover and click it
3. there is no not-allowed cursor

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.