[Button] Fix disabled button text color

[laurkim]

WHY are these changes introduced?

Fixes disabled button text color that was flagged on ContextualSaveBar during v12 bug hunt.

WHAT is this pull request doing?

Updates disabled button styles in ContextualSaveBar.

ContextualSaveBar — before

ContextualSaveBar — after

How to 🎩

Storybook

🖥 Local development instructions
🗒 General tophatting guidelines
📄 Changelog guidelines

Copy-paste this code in playground/Playground.tsx:

import React from 'react';

import {Page, Frame, ContextualSaveBar} from '../src';

export function Playground() {
  return (
    <Page title="Playground">
      {/* Add the code you want to test in here */}
      <div style={{height: '250px'}}>
        <Frame
          logo={{
            width: 86,
            contextualSaveBarSource:
              'https://cdn.shopify.com/s/files/1/2376/3301/files/Shopify_Secondary_Inverted.png',
          }}
        >
          <ContextualSaveBar
            message="Unsaved changes"
            saveAction={{
              onAction: () => console.log('add form submit logic'),
              loading: false,
              disabled: true,
            }}
            discardAction={{
              onAction: () => console.log('add clear form logic'),
            }}
          />
        </Frame>
      </div>
    </Page>
  );
}

🎩 checklist

• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility
• Updated the component's README.md with documentation changes
• Tophatted documentation changes in the style guide

[laurkim]

/snapit

[github-actions]

🫰✨ Thanks @laurkim! Your snapshot has been published to npm.

Test the snapshot by updating your package.json with the newly published version:

yarn add @shopify/polaris@0.0.0-snapshot-release-20231031134300

[aveline]

I think this should actually be --p-color-text-brand-on-bg-fill to set the color directly to a token value rather than an intermediary component custom property.

[laurkim]

Thanks for flagging this @aveline!

Had an offline conversation with @aveline and @sarahill and decided to update this pr to only change styling in the ContextualSaveBar component where the issue was first reported, as opposed to change button styling for all disabled Buttons 👍