Changeset 55246 for trunk/src/wp-includes/blocks/heading.php

Block Editor: Updated the WordPress packages to include Gutenberg 15.1.0 changes.

In addition to all the packages being updated to the latest versions,
this commit also includes some mandatory changes to avoid editor breakage:

• Update React to to 18.2.0.
• Add the right stylesheets to support iframed block editors.

Props ntsekouras, mamaduka, flixos90, desrosj, peterwilsoncc.
See #57471.