Support single IP address on all card based transactions

Spreedly now only supports single IP addresses with a valid format in transaction.ip. Please see the previous changelog notification.

In cases where an IP address is entered incorrectly or with multiple IPs, the following errors may occur:

• multiple_addresses_not_allowed: "Multiple IP addresses are not allowed. Please provide only one valid IP address."
• invalid_format: "Invalid IP address format. Please provide a valid IPv4 or IPv6 address."