Enqueue 'wc-credit-card-form' before displaying credit card form

The commit c0b7429 failed to keep the line that enqueued 'wc-credit-card-form' script when the method WC_Payment_Gateway::credit_card_form() was renamed to WC_Payment_Gateway_CC::form().

includes/gateways/class-wc-payment-gateway-cc.php

@@ -50,6 +50,8 @@ class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 	 * @since 2.6.0
 	 */
 	public function form() {
+		wp_enqueue_script( 'wc-credit-card-form' );
+
 		$html   = '';
 		$fields = array();