Accessibility: Update disabled text color from Gray 10 to Gray 50 for better contrast in checkout

[ivan-ottinger]

Resolves DOTCOM-13280

Proposed Changes

• update disabled text color from Gray 10 to Gray 50

Before	After

Note

I have tried a bit lighter shade of gray than 50, but it already triggered the contrast error

Why are these changes being made?

• a55edfa4e3bf-linear-project

Testing Instructions

• Check out the PR brach and build it with yarn start (or use Calypso Live).
• Add any product to your cart and head over to the checkout page.
• Click on the "Edit" button by your contact details.
• Look at the "Pick a payment method" heading below. It should be in darker gray color.
• If you install the axe DevTools extension (https://chromewebstore.google.com/detail/axe-devtools-web-accessib/lhdoppojpmngadmnindnejefpokejbdd) and scan the checkout page, the following contrast issue shoulln't be there anymore:

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-146466

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-146466&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-146466&env=a8c-for-agencies

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• notifications
• odyssey-stats
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug fix/checkout-page-pick-a-payment-method-heading-contrast on your sandbox.

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[wojtekn]

The issue is fixed - the contrast matches the recommended level now.

[katinthehatsite]

The contrast looks good to me and I do not see the error anymore on my end:

[ivan-ottinger]

Thank you for your reviews, Wojtek & Kat.