MAGETWO-53798: Braintree Paypal button is active before checkout is loaded

Author: viktym

app/code/Magento/Braintree/view/frontend/templates/paypal/button.phtml

@@ -27,7 +27,7 @@ $config = [
        data-locale="<?php /* @noEscape */ echo $block->getLocale(); ?>"
        data-amount="<?php /* @noEscape */ echo $block->getAmount(); ?>"
        id="<?php /* @noEscape */ echo $id; ?>"
-       class="action-braintree-paypal-logo">
+       class="action-braintree-paypal-logo" disabled>
         <img class="braintree-paypal-button-hidden"
              src="https://checkout.paypal.com/pwpp/2.17.6/images/pay-with-paypal.png"
              alt="Pay with PayPal"/>