fix(button): update focus outline and offset

[saiponnada]

Fixes #2075

• This PR contains CSS changes
• This PR does not contain CSS changes

Description

• For button:btn & a.fake-btn:focus added outline for :focus-visible pseudo selector

Notes

• Outline color need to be changed consistently across all buttons and other interactive elements. Update Buttons to Design Spec  #2421
• Another issue noticed is the focus overlapping on skin docs site when multiple buttons are adjacent to each other.

Screenshots

Primary Button

Checklist

• I verify the build is in a non-broken state
• I verify all changes are within scope of the linked issue

• I regenerated all CSS files under dist folder
• I tested the UI in all supported browsers
• I did a visual regression check of the components impacted by doing a Percy build and approved the build
• I tested the UI in dark mode and RTL mode
• I added/updated/removed Storybook coverage as appropriate

[changeset-bot]

🦋 Changeset detected

Latest commit: 12f9923

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@ebay/skin	Minor

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[agliga]

LGTM
Im a bit worried about the overlap, but its probably fine for now.