fix(rux-timeline): added left/right/both border to selected partial events

[kiley-mitti]

Brief Description

Added borders to partial events even when selected. The borders are color/palette/neutral/1000 as they appear on the figma specs. This allows users to know that selected partial events are still partial events.

JIRA Link

ASTRO-4844

Related Issue

General Notes

Motivation and Context

Previously, when a partial timeline event was selected it would lose the dashed left/right border which indicated it as a partial event. Adding them back in a neutral color when selected, brings back the visual queue.

Issues and Limitations

Types of changes

• [x] Bug fix
• [ ] New feature
• [ ] Breaking change

Checklist

• [ ] This PR adds or removes a Storybook story.
• [ ] I have added tests to cover my changes.
• [x] Regressions are passing and/or failures are documented
• [x] Changes have been checked in evergreen browsers

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⚠️ No Changeset found

Latest commit: c8b329ace6fe941e6576bd6e03278401ba608801

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