[Bug] Button border and background color fixes for Secondary variants

[narin]

Ticket department-of-veterans-affairs/va-mobile-app#7330

Description of Change

• Updates border color for Secondary variant in dark mode to #58b4ff (colorUswdsSystemColorBlueVivid30)
• Updates background colors for Secondary and BaseSecondary variants to be transparent instead of black in both light and dark mode
• Update link to correct documentation URL
• Sort Storybook variants using underscore workaround

Testing Packages

Screenshots/Video

Testing

• Tested on iOS
• Tested on Android
• Tested on Web

PR Checklist

Code reviewer validation:

• General
  • PR is linked to ticket(s)
  • Acceptance criteria:
    • All satisfied or
    • Documented reason for not being performed or
    • Split to separate ticket and ticket is linked by relevant AC(s)
  • Above PR sections adequately filled out
  • If any breaking changes, in accordance with the pre-1.0.0 versioning guidelines: a CU ticket has been created for the VA Mobile App detailing necessary adjustments with the package version that will be published by this ticket
• Code
  • Tests are included if appropriate (or split to separate ticket)
  • New functions have proper TSDoc annotations

Publish

If changes warrant a new version per the versioning guidelines and the PR is approved and ready to merge:

• Merge main into branch
• Publish new version
• Merge branch to main

[TimRoe]

Should we have a 'transparent' token?

@jessicawoodin thoughts?

[jessicawoodin]

In Figma, we wouldn't use a design token for this, so I'm leaning towards not creating one here either. In Figma, if we wanted to make something transparent, we just wouldn't apply a "fill color" to that layer which seems consistent with how it's being done here.

[TimRoe]

Approved. Did discover and created a bug poking at it in Web Storybook, but it appeared not directly related to this ticket (as it is also broken on the published Storybook).