The Authorize.Net payment integration now uses the newer signature key method required by Authorize.Net instead of the older MD5 approach. This keeps payment validation compatible with the provider and helps maintain secure transaction processing for businesses using this payment option.

Changes in mater branch to reflect odoo/odoo#34670

MD5 is no longer used by authorize.net, switch to sha512 with
a signature key.

Both fields remain necessary for the integration to work.