Fix/app shell frame tweaks

[adamnel]

Description

General theme tweaks, mostly changing base surface color from pinkish to blueish.

What's included?

• Change surface and foreground colors to a more blue tint (as opposed to the pinkish previously)
• Change default color of non-selected nav items
• Change default color of non-header body text
• Remove extra tracking from button typography

Test Steps

• [ ] npm run storybook
• [ ] then navigate to the app shell story
• [ ] compare against live product

General Tests for Every PR

• [ ] npm run start still works.
• [ ] npm run lint passes.
• [ ] npm run stylelint passes.
• [ ] npm test passes and code coverage is not lower.
• [ ] npm run build still works.

Screenshots

Before

After

[owilliams320]

Can we get some screen shots please

[owilliams320]

:tada: This PR is included in version 8.17.0 :tada:

The release is available on:

• v8.17.0
• GitHub release

Your semantic-release bot :package::rocket: