Webfonts: increase priority of init hook to account for block reregis…

…tration (#41569)

* `gutenberg_register_webfonts_from_theme_json()` calls `WP_Theme_JSON_Resolver_Gutenberg::get_merged_data()`, which instantiates `WP_Theme_JSON_Gutenberg()`;
Gutenberg server-side blocks are registered via the init hook with a priority value of `20`. E.g., `add_action( 'init', 'register_block_core_image', 20 )`;
This priority value is added dynamically during the build. See: tools/webpack/blocks.js.
We want to make sure Gutenberg blocks are re-registered before any Theme_JSON operations take place so that we have access to updated merged data.

* Remove evil space

lib/experimental/register-webfonts-from-theme-json.php

@@ -174,4 +174,9 @@ function gutenberg_add_registered_webfonts_to_theme_json( $data ) {
 	return $data;
 }
 
-add_action( 'init', 'gutenberg_register_webfonts_from_theme_json' );
+// `gutenberg_register_webfonts_from_theme_json()` calls `WP_Theme_JSON_Resolver_Gutenberg::get_merged_data()`, which instantiates `WP_Theme_JSON_Gutenberg()`;
+// Gutenberg server-side blocks are registered via the init hook with a priority value of `20`. E.g., `add_action( 'init', 'register_block_core_image', 20 )`;
+// This priority value is added dynamically during the build. See: tools/webpack/blocks.js.
+// We want to make sure Gutenberg blocks are re-registered before any Theme_JSON operations take place
+// so that we have access to updated merged data.
+add_action( 'init', 'gutenberg_register_webfonts_from_theme_json', 21 );