Shopping: Support custom CTA text

[swissspidy]

Feature Description

As of very recently, the default CTA text for the shopping attachment ("Shop now") can be customized, just like for regular page attachments / outlinks.

See ampproject/amphtml#38080

We now want to add support for this in the editor as well in the PageAttachmentPanel.

To-do:

• Add cta-text attribute to amp-story-shopping-attachment allowlist in KSES
  • Add test for it
• Add CTA text input field to PageAttachmentPanel
  • Maybe refactor this component to split it into two, as it is quite large already
  • Good time to add some JS unit tests for it as well
• Update ProductOutput component to add cta-text attribute
  • Add test for it

Alternatives Considered

Additional Context

Existing CTA text input field for regular page attachments:

[spacedmonkey]

It seems like cta-text attributes has not been updated in the amp plugin. See.

@swissspidy Who do I speak to get this updated.

[swissspidy]

It's @westonruter who regularly updates the spec in the AMP plugin.

[spacedmonkey]

Seems like the last update was nearly 2 months ago. ampproject/amp-wp@4076e7c

[westonruter]

Yeah, it was last updated in ampproject/amp-wp#6956 on March 3. How urgently is this needed?

[swissspidy]

Not urgent. We can patch this ourselves in the meantime. Would be nice to resolve this in May or so though.

[westonruter]

Great. That should align with a 2.3 release and if not a 2.2.5 release with just the spec update.

[westonruter]

I've opened a PR with the update: ampproject/amp-wp#7078