fix(signin): align check-in feedback with reference theme

src/Credits/Signin.php

@@ -338,7 +338,6 @@ class Signin {
                             </div>';
         } else {
             $checkin_btn = '<button type="button" class="but c-blue ml10 p2-10 radius" data-signin-btn'
-                . ' data-signin-idle-label="' . esc_attr__('立即签到', 'aksrt') . '"'
                 . ' data-signin-done-label="' . esc_attr__('今日已签到', 'aksrt') . '">'
                 . '<span data-signin-label>' . esc_html__('立即签到', 'aksrt') . '</span></button>';
         }