Use errors key preferentially over description for gift card JSON errors

[antiBaconMachine]

PR Summary:

Small change that reads errors from an errors property instead of reusing the description field as before.

Why are these changes introduced?

Just trying to keep things clear and concise for other theme developers. Description should in future be for semantic descriptions not structured error messages.

What approach did you take?

For now the backend will send identical payloads in both errors and description keys so this is non breaking. Eventually we'll look to deprecate description for this use case.

Other considerations

Decision log

#	Decision	Alternatives	Rationale	Downsides
1

Visual impact on existing themes

Testing steps/scenarios

• Step 1

Demo links

• Store
• Editor

Checklist

• Added PR summary for release notes
• Requested review from UX (Only for changes that are affecting the experience or perceivable visual details)
• Created a ticket for the help.shopify.com documentation team about updates to theme settings. (Internal-only task)
• Followed theme code principles
• Linted with Theme Check
• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility