Use Arrays as Default Values for Parent and Ancestor in Block Settings

[huubl]

When using ACF PRO v6.3.10, ACF Composer v3.2.0, and the Gutenberg plugin v19.6.0, blocks that are not cached (wp acorn acf:cache) cause errors and prevent them from registering correctly.

The following error appears in the developer console:

acf-pro-blocks.min.js?ver=6.3.10:1 Uncaught TypeError: Cannot read properties of undefined (reading 'attributes')

This issue seems to be related to changes in Block registration: normalize blockType.parent to array and using null defaults.

I made a pull request that change the parent and ancestor defaults to arrays, which fixes the issue.