phone required error fixed

git-svn-id: https://plugins.svn.wordpress.org/authorizenet-aim-payment-gateway-for-woocommerce/trunk@965455 b8457f37-d9ea-0310-8a92-e5e31aec5664
phone required error fixed

git-svn-id: https://plugins.svn.wordpress.org/authorizenet-aim-payment-gateway-for-woocommerce/trunk@965457 b8457f37-d9ea-0310-8a92-e5e31aec5664