Block Editor: Move the `add_action()` call for...

Block Editor: Move the `add_action()` call for `_register_core_block_patterns_and_categories()` to `wp-includes/default-filters.php`.

Follow-up to [48492].

Props desrosj.
Fixes #50669.
Built from https://develop.svn.wordpress.org/trunk@48531


git-svn-id: https://core.svn.wordpress.org/trunk@48293 1a063a9b-81f0-0310-95a4-ce76da25c4cd