Description

remove_theme_support('block-templates'); (applied using the after_setup_theme hook with priority 20) doesn't appear to work when the plugin (v11.9.0) is in use.

Step-by-step reproduction instructions

1. Add the following code to the theme or a plugin
2. The template selector is still visible on the edit post screen.

Screenshots, screen recording, code snippet

add_action('after_setup_theme', 'sht_remove_block_template_support', 20);

function sht_remove_block_template_support() {
	remove_theme_support('block-templates');
}

Environment info

• WordPress 5.8.1
• Gutenberg 11.9.0

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