Update segmented control to use new color theme variables

[jmuzina]

Done

Updates segmented control component so that the divider line between segmented control buttons uses new color theme variables.

This results in a change to the dark theme appearance of the segmented control, as previously it was always using the light theme appearance.

Fixes WD-11861

QA

• Open segmented control example
• Verify that the color of the separator bar between segmented control buttons is correct in each theme.

Check if PR is ready for release

If this PR contains Vanilla SCSS code changes, it should contain the following changes to make sure it's ready for the release:

• PR should have one of the following labels to automatically categorise it in release notes:
  • Feature 🎁, Breaking Change 💣, Bug 🐛, Documentation 📝, Maintenance 🔨.
• Vanilla version in package.json should be updated relative to the most recent release, following semver convention:
  • if CSS class names are not changed it can be bugfix relesase (x.x.X)
  • if CSS class names are changed/added/removed it should be minor version (x.X.0)
  • see the wiki for more details
• Any changes to component class names (new patterns, variants, removed or added features) should be listed on the what's new page.

Screenshots

Before

After

[webteam-app]

Demo

Jenkins

demos.haus

[jmuzina]

Percy does not currently capture a snapshot of the segmented control in dark theme so the Percy build shows no diffs.

Review segmented control in dark theme in demo and staging to see the difference introduced by this PR.

[bartaz]

Perfect, thanks!