Themes: Add is block theme check installer.

Add the is block theme check in installer check.

See #64159.

Author: Ninodevo

src/wp-admin/includes/class-theme-installer-skin.php

@@ -121,7 +121,7 @@ public function after() {
 
 		$install_actions = array();
 
-		if ( current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
+		if ( current_user_can( 'edit_theme_options' ) && ( $theme_info->is_block_theme() || current_user_can( 'customize' ) ) ) {
 			if ( $theme_info->is_block_theme() ) {
 				$customize_url = add_query_arg(
 					array(