UHF-9700: Small accessibility improvements to language toast

[teroelonen]

UHF-9700

What was done

• Convert the language toast to section and add it aria-label.
• Add lang-attribute to places where it is needed.
• Change the close button to same language as to toast as per accessibility expert recommendation.
• Small styling adjustments based on designer recommendations

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-9700
• Run make drush-cr

How to test

• Make sure that there is now section tag around the language toast.
• Make sure that the screen reader pronounces the labels correctly when using the toast.
• Check that code follows our standards.

Continuous documentation

• This feature has been documented/the documentation has been updated.
• This change doesn't require updates to the documentation.

[github-actions]

✅ Tests passed! You can check the output here: https://city-of-helsinki.github.io/drupal-hdbt-visual-regression/pull/1231/html_report/

[github-actions]

✅ Tests passed! You can check the output here: https://city-of-helsinki.github.io/drupal-hdbt-visual-regression/pull/1231/html_report/

[annadruid]

Looks good!