Fix expert plan button

Author: lbartoli79

www/templates/account/signup/step-1.php

@@ -87,7 +87,7 @@
                 </td>
                 <td>
                     <span class="visually-hidden">Sign up for an Expert Plan</span>
-                    <button href="https://www.product.webpagetest.org/expert-plan" id="submit-expert-plan" class="signup-button" type="submit" form="pro-plan-form">
+                    <a href="https://www.product.webpagetest.org/expert-plan" id="submit-expert-plan" class="button signup-button">
                         Start for $<span data-id="plan-price"><?= $expert_plan['monthly'] > 0 ? $expert_plan['monthly'] : "" ?></span><span class="unit" data-id="plan-cycle">/month</span>
                         <div>
                         <small>