(Master issue) Add disabled variation to va-button

[caw310]

Description

This will be the master ticket for work related to Experimental Design - improvements to va-button disabled variation

This ticket will be used to track all the work that is needed to complete the add a disabled variation to button. .
Design: (link to ticket)
Development: (link to ticket)
A11 review: (link to ticket)
Documentation: (link to ticket)

Tasks

• Design: Add component to Figma or update component in Figma
• Development: Build web component and add as component to Storybook or update component and Storybook
• Accessibility review of the web component
• Update documentation site with guidance
• Request Staging review (if needed)
• Publish announcement on #platform-design-system and #design Slack channels

Acceptance Criteria

• Designs in Figma have been published
• Component is published on Storybook
• design.va.gov has been updated
• Staging review has been completed and 'Must' issues are resolved (if applicable)
• Announcement published on slack

[caw310]

Closing as all work related to this will be tracked through Experimental Design - improvements to va-button disabled variation which is the original request.