UHF-7418 Phasing component accessibility changes

[teroelonen]

UHF-7418

What was done

• Changed numbered phasing component to use ol tag instead of ul.
• Switched the before and after pseudo elements other way around so that the number is read first with screen readers.

How to install

• Make sure your instance is up and running on latest dev branch.
  • git pull origin dev
  • make fresh
• Update the HDBT theme
  • composer require drupal/hdbt:dev-UHF-7418_phasing_component_accessibility_changes
• Run make drush-cr

How to test

• Go and create a phasing components: one with just one item, other one with few items. Make sure they have the numbering turned on.
• Save the content and make sure that the layout looks good as before.
• Check with inspector that the structure of the element for the screen reader is so that the number is first. Check the screenshot for what the element should look like.
• Check that code follows our standards

Designers review

• This PR does not need designers review
• This PR has been visually reviewed by a designer (Name of the designer)