Theme app extensions now support conditional app blocks

The visibility of an app block, or app embed block, of a theme app extension can now be controlled based on a custom condition.

The condition can be included in the block's schema with the available_if attribute, and the state of the condition is stored in an app-owned metafield. The metafield can be accessed through the Liquid app object.

To learn more about conditional app blocks, refer to Theme app extensions framework.