Adds a new non-public `WP_REST_Block_Patterns_Controller::migrate_pattern_categories()` method to automatically migrate existing content's pattern categories to the new ones introduced in [55098].
Old to New
`'buttons'` to `'call-to-action'`
`'columns'` to `'text'`
`'query'` to `'posts'`
Reference:
* Part of [https://github.com/WordPress/gutenberg/pull/46144 Gutenberg PR 46144]
Follow-up to [55098], [53152].
Props ntsekouras, annezazu, jameskoster, joen, hellofromTonya, mcsf, paaljoachim, ryelle.
Fixes#57532.
Built from https://develop.svn.wordpress.org/trunk@55125
git-svn-id: http://core.svn.wordpress.org/trunk@54658 1a063a9b-81f0-0310-95a4-ce76da25c4cd