Added content to shortcode cache key generation

[wcha-peter]

The caching functionality for ux_cv_api4_get didn't include the shortcode content, which causes a couple of issues:

• Any changes to the shortcode content without updating the shortcode parameters would require the cache to expire before showing updates
• If the same shortcode parameters were used in multiple locations across the site with different content, the cache would see them as the same and return the same content for both of them.

[wcha-peter]

Feature implemented to release 1.9.4 using post ids