[Backport] Issue #10645 - Allow BEM class via attribute tag. Public

[amol2jcommerce]

Original Pull Request

#10655

Description

Before the fix, classes with -- in them was replaced with a single - so result with input class--1 appears as class-1, breaking the BEM convention.

Fixed Issues

1. Adding BEM class in XML via attribute tag causes class to be rewritten #10645: Adding BEM class in XML via attribute tag causes class to be rewritten

Manual testing scenarios

1. Go to default.xml
2. Add attribute tag with a class to the body element i.e. <attribute name="class" value="class--1" />
3. Clear cache and reload page

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 @amol2jcommerce. Thank you for your contribution
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[magento-engcom-team]

Hi @dmytro-ch, thank you for the review.
ENGCOM-4516 has been created to process this Pull Request

[VasylShvorak]

✔️ QA passed

[ghost]

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