Xanadu: Add strict types to remaining php files (#7549)

xanadu/patterns/404.php

@@ -4,6 +4,8 @@
  * Slug: xanadu/404
  * Inserter: no
  */
+
+declare( strict_types = 1 );
 ?>
 
 <!-- wp:heading {"textAlign":"center","level":1,"fontSize":"x-large"} -->

xanadu/patterns/footer.php

@@ -5,6 +5,8 @@
  * Categories: footer
  * Block Types: core/template-part/footer
  */
+
+declare( strict_types = 1 );
 ?>
 
 <!-- wp:spacer {"height":"50px"} -->

xanadu/patterns/header.php

@@ -5,6 +5,8 @@
  * Categories: header
  * Block Types: core/template-part/header
  */
+
+declare( strict_types = 1 );
 ?>
 
 <!-- wp:group {"style":{"spacing":{"padding":{"top":"var:preset|spacing|30","right":"var:preset|spacing|30","bottom":"var:preset|spacing|30","left":"var:preset|spacing|30"},"blockGap":"0","margin":{"top":"var:preset|spacing|80","bottom":"var:preset|spacing|80"}}},"layout":{"type":"default"}} -->

xanadu/patterns/no-results.php

@@ -4,6 +4,8 @@
  * Slug: xanadu/no-results
  * Inserter: no
  */
+
+declare( strict_types = 1 );
 ?>
 
 <!-- wp:paragraph {"style":{"spacing":{"margin":{"top":"0px","bottom":"0px"}}}} -->