TP-2084 adjust url and file external links

[IiroJarv]

Actions for applying the changes locally

lando composer install && lando drush deploy

Testing instructions

• Go to a service page with filled url and file field (that the links are filled) with both external and internal links
• Ensure that the links have new icons and they are properly themed
• Ensure text fields still have the original external link symbols
• Repeat above for basic page

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.