Add captcha validation error handling in script.js

A conditional block of code was added to handle the case when 'captcha_key' is not defined. This is to manage the scenario when captcha verification fails, providing an error message to the user and thus improving user experience.

exmplate/script.js

@@ -165,6 +165,11 @@
                 setError(errorMessage, button);
                 return
             }
+            if (typeof data.captcha_key === 'undefined') {
+                setError('Произошла ошибка!', button);
+                return
+            }
+
             shadow.querySelector('button.button-open-window-captcha').remove();
             let captchaVerified = document.createElement('div');
             captchaVerified.innerHTML = `<span class="captcha-verified">Ура!!! Проверку прошли!</span><input type="hidden" name="captcha-verified" value="${ data.captcha_key }">`;