chore: loading state for Button

[jaredcwhite]

Issue Overview

This PR addresses #64

Description

This PR adds a loadingMessage prop which will display a loading spinner, make clicks disabled, and also announce an ARIA live message.

How Can This Be Tested/Reviewed?

This Storybook example: https://deploy-preview-67--storybook-ui-seeds.netlify.app/?path=/story/actions-button--loading-button

Checklist:

• [ ] I have added QA notes to the issue with applicable URLs
• [x] I have performed a self-review of my own code
• [x] I have reviewed the changes in a desktop view
• [ ] I have reviewed the changes in a mobile view
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have exported any new components
• [x] My commit message(s) and PR title are polished in the conventional commit format, and any breaking changes are indicated in the message and are well-described

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[github-actions[bot]]

:tada: This PR is included in version 1.12.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: