saveEntityRecord() returns 404 when trying to save a template given its id and content

[Aljullu]

Description

Using saveEntityRecord() to save a template stopped working in a recent update of Gutenberg.

I believe the issue was introduced in #67125 (cc @ellatrix), specifically where the wp_template rest_base is modified:

gutenberg/lib/compat/wordpress-6.9/template-activate.php

Lines 3 to 15 in 99d25fb

	// How does this work?
	// 1. For wp_template, we remove the custom templates controller, so it becomes
	// a normal posts endpoint, modified slightly to allow auto-drafts.
	add_filter( 'register_post_type_args', 'gutenberg_modify_wp_template_post_type_args', 10, 2 );
	function gutenberg_modify_wp_template_post_type_args( $args, $post_type ) {
	if ( 'wp_template' === $post_type ) {
	$args['rest_base'] = 'wp_template';
	$args['rest_controller_class'] = 'Gutenberg_REST_Templates_Controller';
	$args['autosave_rest_controller_class'] = null;
	$args['revisions_rest_controller_class'] = null;
	}
	return $args;
	}

Step-by-step reproduction instructions

1. Switch your theme to TT4.
2. Add this code snippet somewhere in your site/plugin:

const { saveEntityRecord } = dispatch( coreStore );
saveEntityRecord(
	'postType',
	'wp_template',
	{
		id: 'twentytwentyfour//home',
		content: 'test',
	},
	{
		throwOnError: true,
	}
);

3. With Gutenberg disabled, notice a query to /wp-json/wp/v2/templates/twentytwentyfour//home is done, and it works. With Gutenberg enabled, the query is done to /wp-json/wp/v2/wp_template/twentytwentyfour//home and it returns this error: No route was found matching the URL and request method..

Screenshots, screen recording, code snippet

No response

Environment info

• Gutenberg nightly or trunk.
• WP 6.8.2.

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure