Changes to Create a counterparty

added the new optional request property rail/oneOf[subschema #2]/disabledNetworks

added the new arc-testnet enum value to the counterparty/invite/onchainNetwork response property for the response status 201

added the new arc-testnet enum value to the counterparty/rails/items/oneOf[subschema #2]/disabledNetworks/items response property for the response status 201

added the new arc-testnet enum value to the counterparty/rails/items/oneOf[subschema #2]/network response property for the response status 201

added the new arc-testnet enum value to the counterparty/rails/items/oneOf[subschema #2]/preferredNetwork response property for the response status 201

added the new arc-testnet enum value to the request property rail/oneOf[subschema #2]/network

added the optional property counterparty/rails/items/oneOf[subschema #2]/disabledNetworks to the response with the 201 status

added the optional property counterparty/rails/items/oneOf[subschema #2]/preferredNetwork to the response with the 201 status

added the optional property counterparty/invite/onchainNetwork to the response with the 201 status