Pattern block: update frontend render code to match the new version of syncStatus attrib

[glendaviesnz]

What?

Updates frontend render code so that blocks with no syncStatus attrib do not get wrapped in a block wrapper.

Why?

This matches the latest iteration of the synced block setup implemented in #50533, but the frontend code was overlooked in this change. This fix makes sure the change is backwards compat with existing Pattern blocks that do not have a wrapper.

How?

Modified index.php code to return early with previous version of render if no syncStatus attrib set.

Testing Instructions

• Add the following block markup in the code editor view of post editor and save:

 <!-- wp:pattern {"slug":"twentytwentythree/cta"} /-->
 <!-- wp:pattern {"slug":"twentytwentythree/cta","syncStatus":"partial","className":"my-custom-classname"} /-->

• Load the front end view of the post and check that the first CTA block has not wp-block-pattern wrapper and the second one does. Also check that the custom classname displays on the second one

Screenshots or screencast

[aaronrobertshaw]

Thanks for cleaning this up 👍

✅ The first pattern without syncStatus is not wrapped in editor or frontend
✅ The second pattern with partial syncing is wrapped in editor & frontend
✅ The pattern block wrapper has correct class names applied

LGTM