Task/tp 2060 toc font sizes

[jussiviitamaki]

Actions necessary for applying the changes: (for example composer install; drush updb; drush cim)

lando composer install && lando drush deploy

Testing instructions:

• Login and go to service work instructions
• Confirm toc links have even margins
• Lower window height
• Confirm scroll bar appears to toc and it can be scroller
• Confirm all links show up while scrolling the toc
• Zoom page in and out and confirm toc fonts doesn't jump up/down

Review checklist:

• The code conforms to Drupal coding standards
• I have reviewed the code for security and quality issues
• I have tested the code with the proper user roles
• I have moved the ticket to the approval lane, added testing instructions and assigned it to the product owner.