Add support for detecting wide-aligned support declared through theme.json

[skorasaurus]

Currently, blocks that have wide and full align attributes are conditionally loaded by detectingget_theme_support( 'align-wide');

Since WP 5.8; support for wide and full align blocks can be added through theme.json by declaring values for the contentsize and widesize ; removing the need for a theme to specifically issue add_theme_support( 'align-wide').

This needs additional condition/logic to detect wide-align block support in theme.json; PR forthcoming.

ref: WordPress/gutenberg#35330