Update and fix failing tests

MAILPOET-6323

packages/js/email-editor/src/types/wordpress-modules.ts

@@ -37,7 +37,7 @@ declare module '@wordpress/editor' {
 	export const PostPreviewButton: ComponentType<
 		WPPostPreviewButton.Props & {
 			className?: string;
-			role: string;
+			role?: string;
 			textContent: JSX.Element;
 			onPreview: () => void;
 		}

packages/php/email-editor/src/Engine/class-email-editor.php

@@ -288,7 +288,7 @@ class Email_Editor {
 
 		add_filter(
 			'mailpoet_email_editor_preview_post_template_html',
-			function ( $post ) {
+			function () use ( $post ) {
 				// Generate HTML content for email editor post.
 				return $this->send_preview_email->render_html( $post );
 			}