Address design and guidance issues in 'Summary card' contribution

[calvin-lau-sig7]

What

Decide how to address the design issues raised by the working group in their review of the summary card (following #2214).

Related issues:
https://github.com/alphagov/design-system-team-internal/issues/596
#2221
#2224

Why

So we know what we're building and can publish the component.

Who needs to work on this

Designer, Content designer, developer

Who needs to review this

Share with the whole team before finalising decisions

Done when

Comms

• Summarise recommendations from working group feedback meeting (Notes)
• Made decisions on how to address (add to decisions doc?)
• Post update on backlog issue Summary card govuk-design-system-backlog#210

[calvin-lau-sig7]

Draft summary in this doc.

Will check with 1-2 of the folks who were at the meeting when they're in to make sure it's accurate.

[kellylee-gds]

@calvin-lau-sig7 I'm going to separate this card into two - the latter part about iterating the component I'll pop into the backlog for a later sprint. I'll move this one to done