Move old versions code to own class

[MAILPOET-1316]

assets/js/src/notice-php-warning.jsx

@@ -0,0 +1,15 @@
+import jQuery from 'jquery';
+
+jQuery(($) => {
+  $(document).on('click', '.notice-php-warning .notice-dismiss', function xyz() {
+    const type = $(this).closest('.notice-php-warning').data('notice');
+    $.ajax(window.ajaxurl,
+      {
+        type: 'POST',
+        data: {
+          action: 'dismissed_notice_handler',
+          type,
+        },
+      });
+  });
+});