Recompile assets to fix notification icons

[Scotchester]

We accidentally lost some of the icon CSS updates. This fixes that by recompiling the assets.

Testing

1. Pull branch
2. npm start
3. Visit http://localhost:4000/page-components/form-fields.html#states-1
4. Observe correctly positioned icons.

Screenshots

Before

After

Checklist

• [x] Changes are limited to a single goal (no scope creep)
• [x] Code can be automatically merged (no conflicts)
• [x] Code follows the standards laid out in the front end playbook
• [x] Passes all existing automated tests
• [x] New functions include new tests
• [x] New functions are documented (with a description, list of inputs, and expected output)
• [x] Placeholder code is flagged
• [x] Visually tested in supported browsers and devices
• [x] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)

[nataliafitzgerald]

@Scotchester - The screenshots you've posted for "success" and "warning" look correct to me. I assume the "error" and "action" will follow the same approach. If you can post screenshots of those above I'll take a look, otherwise I'll just assume they're correct too.