Adds the widgets block editor to widgets.php and customize.php
Moves the widgets block editor from Gutenberg into WordPress Core.
- Adds @wordpress/edit-widgets, @wordpress/customize-widgets and
@wordpress/widgets.
- Modifies wp-admin/widgets.php to branch between the old editor and new editor
depending on wp_use_widgets_block_editor().
- Modifies WP_Customize_Widgets to branch between the old editor control and new
editor control depending on wp_use_widgets_block_editor().
Follows [50996] which was missing these files.
See #51506.
Props isabel_brison, TimothyBlynJacobs, andraganescu, kevin940726, talldanwp.